diff --git a/apps/bookmark.c b/apps/bookmark.c
index 8d60de28fe..ed85ff6222 100644
--- a/apps/bookmark.c
+++ b/apps/bookmark.c
@@ -51,19 +51,19 @@
 #define MAX_BOOKMARK_SIZE  350
 #define RECENT_BOOKMARK_FILE ROCKBOX_DIR "/most-recent.bmark"
 
-static bool  add_bookmark(char* bookmark_file_name, char* bookmark);
+static bool  add_bookmark(const char* bookmark_file_name, const char* bookmark);
 static bool  bookmark_load_menu(void);
-static bool  check_bookmark(char* bookmark);
+static bool  check_bookmark(const char* bookmark);
 static char* create_bookmark(void);
-static bool  delete_bookmark(char* bookmark_file_name, int bookmark_id);
-static void  display_bookmark(char* bookmark,
+static bool  delete_bookmark(const char* bookmark_file_name, int bookmark_id);
+static void  display_bookmark(const char* bookmark,
                               int bookmark_id, 
                               int bookmark_count);
-static void  say_bookmark(char* bookmark,
+static void  say_bookmark(const char* bookmark,
                           int bookmark_id);
-static bool  generate_bookmark_file_name(char *in);
-static char* get_bookmark(char* bookmark_file, int bookmark_count);
-static bool  parse_bookmark(char *bookmark,
+static bool  generate_bookmark_file_name(const char *in);
+static char* get_bookmark(const char* bookmark_file, int bookmark_count);
+static bool  parse_bookmark(const char *bookmark,
                             int *resume_index,
                             int *resume_offset,
                             int *resume_seed,
@@ -75,10 +75,10 @@ static bool  parse_bookmark(char *bookmark,
                             bool *shuffle,
                             char* file_name,
                             unsigned int max_file_name_size);
-static char* select_bookmark(char* bookmark_file_name);
+static char* select_bookmark(const char* bookmark_file_name);
 static bool  system_check(void);
 static bool  write_bookmark(bool create_bookmark_file);
-static int   get_bookmark_count(char* bookmark_file_name);
+static int   get_bookmark_count(const char* bookmark_file_name);
 
 static char global_temp_buffer[MAX_PATH+1];
 static char global_bookmark_file_name[MAX_PATH];
@@ -332,7 +332,7 @@ static bool write_bookmark(bool create_bookmark_file)
 /* ----------------------------------------------------------------------- */
 /* This function adds a bookmark to a file.                                */
 /* ------------------------------------------------------------------------*/
-static bool add_bookmark(char* bookmark_file_name, char* bookmark)
+static bool add_bookmark(const char* bookmark_file_name, const char* bookmark)
 {
     int    temp_bookmark_file = 0;
     int    bookmark_file = 0;
@@ -447,7 +447,7 @@ static char* create_bookmark()
         return NULL;
 }
 
-static bool check_bookmark(char* bookmark)
+static bool check_bookmark(const char* bookmark)
 {
     return parse_bookmark(bookmark,
                           NULL,NULL,NULL, NULL,
@@ -459,7 +459,7 @@ static bool check_bookmark(char* bookmark)
 /* This function will determine if an autoload is necessary.  This is an   */
 /* interface function.                                                     */
 /* ------------------------------------------------------------------------*/
-bool bookmark_autoload(char* file)
+bool bookmark_autoload(const char* file)
 {
     int  key;
     int  fd;
@@ -537,7 +537,7 @@ bool bookmark_autoload(char* file)
 /* This function loads the bookmark information into the resume memory.    */
 /* This is an interface function.                                          */
 /* ------------------------------------------------------------------------*/
-bool bookmark_load(char* file, bool autoload)
+bool bookmark_load(const char* file, bool autoload)
 {
     int  fd;
     bool success = true;
@@ -587,7 +587,7 @@ bool bookmark_load(char* file, bool autoload)
 }
 
 
-static int get_bookmark_count(char* bookmark_file_name)
+static int get_bookmark_count(const char* bookmark_file_name)
 {
     int read_count = 0;
     int file = open(bookmark_file_name, O_RDONLY);
@@ -613,7 +613,7 @@ static int get_bookmark_count(char* bookmark_file_name)
 /* This displays a the bookmarks in a file and allows the user to          */
 /* select one to play.                                                     */
 /* ------------------------------------------------------------------------*/
-static char* select_bookmark(char* bookmark_file_name)
+static char* select_bookmark(const char* bookmark_file_name)
 {
     int bookmark_id = 0;
     int bookmark_id_prev = -1;
@@ -732,7 +732,7 @@ static char* select_bookmark(char* bookmark_file_name)
 /* This function takes a location in a bookmark file and deletes that      */
 /* bookmark.                                                               */
 /* ------------------------------------------------------------------------*/
-static bool delete_bookmark(char* bookmark_file_name, int bookmark_id)
+static bool delete_bookmark(const char* bookmark_file_name, int bookmark_id)
 {
     int temp_bookmark_file = 0;
     int bookmark_file = 0;
@@ -784,7 +784,7 @@ static bool delete_bookmark(char* bookmark_file_name, int bookmark_id)
 /* ----------------------------------------------------------------------- */
 /* This function parses a bookmark and displays it for the user.           */
 /* ------------------------------------------------------------------------*/
-static void display_bookmark(char* bookmark,
+static void display_bookmark(const char* bookmark,
                              int bookmark_id,
                              int bookmark_count)
 {
@@ -908,7 +908,7 @@ static void display_bookmark(char* bookmark,
 /* ----------------------------------------------------------------------- */
 /* This function parses a bookmark, says the voice UI part of it.          */
 /* ------------------------------------------------------------------------*/
-static void say_bookmark(char* bookmark,
+static void say_bookmark(const char* bookmark,
                          int bookmark_id)
 {
     int resume_index;
@@ -952,7 +952,7 @@ static void say_bookmark(char* bookmark,
 /* in the file, it will return the last one.                               */
 /* It also returns the index number of the bookmark in the file            */
 /* ------------------------------------------------------------------------*/
-static char* get_bookmark(char* bookmark_file, int bookmark_count)
+static char* get_bookmark(const char* bookmark_file, int bookmark_count)
 {
     int read_count = -1;
     int result = 0;
@@ -989,7 +989,7 @@ static char* get_bookmark(char* bookmark_file, int bookmark_count)
 /* validates the bookmark.  Passing in NULL for an output variable         */
 /* indicates that value is not requested.                                  */
 /* ----------------------------------------------------------------------- */
-static bool parse_bookmark(char *bookmark,
+static bool parse_bookmark(const char *bookmark,
                            int *resume_index,
                            int *resume_offset,
                            int *resume_seed,
@@ -1123,7 +1123,7 @@ static bool parse_bookmark(char *bookmark,
 /* it would be here that the centralized/decentralized bookmark code       */
 /* could be placed.                                                        */
 /* ----------------------------------------------------------------------- */
-static bool generate_bookmark_file_name(char *in)
+static bool generate_bookmark_file_name(const char *in)
 {
     int len = strlen(in);
 
diff --git a/apps/bookmark.h b/apps/bookmark.h
index bff58f67a8..2f8b58af7e 100644
--- a/apps/bookmark.h
+++ b/apps/bookmark.h
@@ -25,8 +25,8 @@ bool bookmark_menu(void);
 bool bookmark_autobookmark(void);
 bool bookmark_create_menu(void);
 bool bookmark_mrb_load(void);
-bool bookmark_autoload(char* file);
-bool bookmark_load(char* file, bool autoload);
+bool bookmark_autoload(const char* file);
+bool bookmark_load(const char* file, bool autoload);
 void bookmark_play(char* resume_file, int index, int offset, int seed);
 
 #endif /* __BOOKMARK_H__ */
diff --git a/apps/debug_menu.c b/apps/debug_menu.c
index 0f4305640e..9fd2e33749 100644
--- a/apps/debug_menu.c
+++ b/apps/debug_menu.c
@@ -202,7 +202,7 @@ bool dbg_mpeg_thread(void)
 
 
 /* Tool function to calculate a CRC16 across some buffer */
-unsigned short crc_16(unsigned char* buf, unsigned len)
+unsigned short crc_16(const unsigned char* buf, unsigned len)
 {
     /* CCITT standard polynomial 0x1021 */
     static const unsigned short crc16_lookup[16] = 
diff --git a/apps/filetypes.c b/apps/filetypes.c
index d7151ca661..09090c30d4 100644
--- a/apps/filetypes.c
+++ b/apps/filetypes.c
@@ -72,11 +72,11 @@ static char   string_buffer[STRING_BUFFER_SIZE];
 
 /* prototypes */
 #ifdef HAVE_LCD_BITMAP
-static char*  string2icon(char*);
+static char*  string2icon(const char*);
 #endif
-static char*  get_string(char*);
+static char*  get_string(const char*);
 static int    find_attr_index(int);
-static bool   read_config(char*);
+static bool   read_config(const char*);
 static void   rm_whitespaces(char*);
 static void   scan_plugins(void);
 
@@ -160,7 +160,7 @@ int   filetype_get_icon(int attr)
 }
 
 /* get plugin */
-char* filetype_get_plugin(struct entry* file)
+char* filetype_get_plugin(const struct entry* file)
 {
     int ix;
 
@@ -197,7 +197,7 @@ bool filetype_supported(int attr)
 }
 
 /* get the "dynamic" attribute for an extension */
-int filetype_get_attr(char* name)
+int filetype_get_attr(const char* name)
 {
     int i;
 
@@ -239,7 +239,7 @@ int filetype_load_menu(struct menu_item*  menu,int max_items)
 }
 
 /* start a plugin with an argument (called from onplay.c) */
-int filetype_load_plugin(char* plugin, char* file)
+int filetype_load_plugin(const char* plugin, char* file)
 {
     snprintf(plugin_name,sizeof(plugin_name),"%s/%s.rock",
              VIEWERS_DIR,plugin);
@@ -427,7 +427,7 @@ static void scan_plugins(void)
 }
 
 /* read config file (or cahe file) */
-bool read_config(char* file)
+bool read_config(const char* file)
 {
     enum {extension,
           plugin,
@@ -584,7 +584,7 @@ bool read_config(char* file)
 
 #ifdef HAVE_LCD_BITMAP
 /* convert an ascii hexadecimal icon to a binary icon */
-static char* string2icon(char* str)
+static char* string2icon(const char* str)
 {
     char tmp[ICON_LENGTH*2];
     char *cp;
@@ -634,7 +634,7 @@ static char* string2icon(char* str)
 #endif
 
 /* get string from buffer */
-static char* get_string(char* str)
+static char* get_string(const char* str)
 {
     unsigned int l=strlen(str)+1;
     char* cp;
diff --git a/apps/filetypes.h b/apps/filetypes.h
index c5bccf4498..e72dd6ffd3 100644
--- a/apps/filetypes.h
+++ b/apps/filetypes.h
@@ -23,17 +23,17 @@
 #include <tree.h>
 #include <menu.h>
 
-int filetype_get_attr(char*);
+int filetype_get_attr(const char*);
 #ifdef HAVE_LCD_BITMAP
 const char* filetype_get_icon(int);
 #else
 int   filetype_get_icon(int);
 #endif
-char* filetype_get_plugin(struct entry*);
+char* filetype_get_plugin(const struct entry*);
 void  filetype_init(void);
 bool  filetype_supported(int);
 int   filetype_load_menu(struct menu_item*, int);
-int   filetype_load_plugin(char*,char*);
+int   filetype_load_plugin(const char*, char*);
 
 struct file_type {
 #ifdef HAVE_LCD_BITMAP
diff --git a/apps/language.c b/apps/language.c
index 2b050c66ef..2b9b6ff30b 100644
--- a/apps/language.c
+++ b/apps/language.c
@@ -28,7 +28,7 @@ extern int printf(const char *format, ...);
 
 static unsigned char language_buffer[MAX_LANGUAGE_SIZE];
 
-int lang_load(char *filename)
+int lang_load(const char *filename)
 {
     int filesize;
     int fd = open(filename, O_RDONLY);
diff --git a/apps/language.h b/apps/language.h
index 454d852c7c..0262864431 100644
--- a/apps/language.h
+++ b/apps/language.h
@@ -25,4 +25,4 @@
 #define LANGUAGE_VERSION 0x02
 
 /* load a given language file */
-int lang_load(char *filename);
+int lang_load(const char *filename);
diff --git a/apps/menu.c b/apps/menu.c
index 5e8a51200a..fccc88479b 100644
--- a/apps/menu.c
+++ b/apps/menu.c
@@ -49,7 +49,7 @@ struct menu {
     int (*callback)(int, int);
 #ifdef HAVE_LCD_BITMAP
     bool use_buttonbar; /* true if a buttonbar is defined */
-    char *buttonbar[3];
+    const char *buttonbar[3];
 #endif
 };
 
@@ -225,7 +225,7 @@ static void put_cursor(int m, int target)
 }
 
 int menu_init(const struct menu_item* mitems, int count, int (*callback)(int, int),
-              char *button1, char *button2, char *button3)
+              const char *button1, const char *button2, const char *button3)
 {
     int i;
 
diff --git a/apps/menu.h b/apps/menu.h
index d097f73a0f..12d934fc18 100644
--- a/apps/menu.h
+++ b/apps/menu.h
@@ -28,7 +28,7 @@ struct menu_item {
 };
 
 int menu_init(const struct menu_item* mitems, int count, int (*callback)(int, int),
-              char *button1, char *button2, char *button3);
+              const char *button1, const char *button2, const char *button3);
 void menu_exit(int menu);
 
 void put_cursorxy(int x, int y, bool on);
diff --git a/apps/playlist.c b/apps/playlist.c
index f702c1ad9d..fa663fe62f 100644
--- a/apps/playlist.c
+++ b/apps/playlist.c
@@ -128,19 +128,19 @@ static struct playlist_info current_playlist;
 static char now_playing[MAX_PATH+1];
 
 static void empty_playlist(struct playlist_info* playlist, bool resume);
-static void new_playlist(struct playlist_info* playlist, char *dir,
-                         char *file);
+static void new_playlist(struct playlist_info* playlist, const char *dir,
+                         const char *file);
 static void create_control(struct playlist_info* playlist);
 static int  check_control(struct playlist_info* playlist);
 static void update_playlist_filename(struct playlist_info* playlist,
-                                     char *dir, char *file);
+                                     const char *dir, const char *file);
 static int add_indices_to_playlist(struct playlist_info* playlist,
                                    char* buffer, int buflen);
 static int add_track_to_playlist(struct playlist_info* playlist,
-                                 char *filename, int position, bool queue,
-                                 int seek_pos);
+                                 const char *filename, int position, 
+                                 bool queue, int seek_pos);
 static int add_directory_to_playlist(struct playlist_info* playlist,
-                                     char *dirname, int *position, bool queue,
+                                     const char *dirname, int *position, bool queue,
                                      int *count, bool recurse);
 static int remove_track_from_playlist(struct playlist_info* playlist,
                                       int position, bool write);
@@ -149,18 +149,18 @@ static int randomise_playlist(struct playlist_info* playlist,
                               bool write);
 static int sort_playlist(struct playlist_info* playlist, bool start_current,
                          bool write);
-static int get_next_index(struct playlist_info* playlist, int steps);
+static int get_next_index(const struct playlist_info* playlist, int steps);
 static void find_and_set_playlist_index(struct playlist_info* playlist,
                                         unsigned int seek);
 static int compare(const void* p1, const void* p2);
 static int get_filename(struct playlist_info* playlist, int seek,
                         bool control_file, char *buf, int buf_length);
 static int format_track_path(char *dest, char *src, int buf_length, int max,
-                             char *dir);
-static void display_playlist_count(int count, char *fmt);
+                             const char *dir);
+static void display_playlist_count(int count, const char *fmt);
 static void display_buffer_full(void);
 static int flush_pending_control(struct playlist_info* playlist);
-static int rotate_index(struct playlist_info* playlist, int index);
+static int rotate_index(const struct playlist_info* playlist, int index);
 
 /*
  * remove any files and indices associated with the playlist
@@ -212,8 +212,8 @@ static void empty_playlist(struct playlist_info* playlist, bool resume)
  * Initialize a new playlist for viewing/editing/playing.  dir is the
  * directory where the playlist is located and file is the filename.
  */
-static void new_playlist(struct playlist_info* playlist, char *dir,
-                         char *file)
+static void new_playlist(struct playlist_info* playlist, const char *dir,
+                         const char *file)
 {
     empty_playlist(playlist, false);
 
@@ -291,7 +291,7 @@ static int check_control(struct playlist_info* playlist)
  * store directory and name of playlist file
  */
 static void update_playlist_filename(struct playlist_info* playlist,
-                                     char *dir, char *file)
+                                     const char *dir, const char *file)
 {
     char *sep="";
     int dirlen = strlen(dir);
@@ -400,8 +400,8 @@ static int add_indices_to_playlist(struct playlist_info* playlist,
  *     PLAYLIST_INSERT_LAST  - Add track to end of playlist
  */
 static int add_track_to_playlist(struct playlist_info* playlist,
-                                 char *filename, int position, bool queue,
-                                 int seek_pos)
+                                 const char *filename, int position,
+                                 bool queue, int seek_pos)
 {
     int insert_position = position;
     unsigned int flags = PLAYLIST_INSERT_TYPE_INSERT;
@@ -523,7 +523,7 @@ static int add_track_to_playlist(struct playlist_info* playlist,
  * Insert directory into playlist.  May be called recursively.
  */
 static int add_directory_to_playlist(struct playlist_info* playlist,
-                                     char *dirname, int *position, bool queue,
+                                     const char *dirname, int *position, bool queue,
                                      int *count, bool recurse)
 {
     char buf[MAX_PATH+1];
@@ -791,7 +791,7 @@ static int sort_playlist(struct playlist_info* playlist, bool start_current,
  * returns the index of the track that is "steps" away from current playing
  * track.
  */
-static int get_next_index(struct playlist_info* playlist, int steps)
+static int get_next_index(const struct playlist_info* playlist, int steps)
 {
     int current_index = playlist->index;
     int next_index    = -1;
@@ -972,7 +972,7 @@ static int get_filename(struct playlist_info* playlist, int seek,
  * Returns absolute path of track
  */
 static int format_track_path(char *dest, char *src, int buf_length, int max,
-                             char *dir)
+                             const char *dir)
 {
     int i = 0;
     int j;
@@ -1037,7 +1037,7 @@ static int format_track_path(char *dest, char *src, int buf_length, int max,
  * Display splash message showing progress of playlist/directory insertion or
  * save.
  */
-static void display_playlist_count(int count, char *fmt)
+static void display_playlist_count(int count, const char *fmt)
 {
     lcd_clear_display();
 
@@ -1120,7 +1120,7 @@ static int flush_pending_control(struct playlist_info* playlist)
 /*
  * Rotate indices such that first_index is index 0
  */
-static int rotate_index(struct playlist_info* playlist, int index)
+static int rotate_index(const struct playlist_info* playlist, int index)
 {
     index -= playlist->first_index;
     if (index < 0)
@@ -1153,7 +1153,7 @@ void playlist_init(void)
 /*
  * Create new playlist
  */
-int playlist_create(char *dir, char *file)
+int playlist_create(const char *dir, const char *file)
 {
     struct playlist_info* playlist = &current_playlist;
 
@@ -1555,7 +1555,7 @@ int playlist_resume(void)
 /* 
  * Add track to in_ram playlist.  Used when playing directories.
  */
-int playlist_add(char *filename)
+int playlist_add(const char *filename)
 {
     struct playlist_info* playlist = &current_playlist;
     int len = strlen(filename);
@@ -1780,7 +1780,8 @@ int playlist_amount(void)
  * playlist indices (required for and only used if !current playlist).  The
  * temp_buffer (if not NULL) is used as a scratchpad when loading indices.
  */
-int playlist_create_ex(struct playlist_info* playlist, char* dir, char* file,
+int playlist_create_ex(struct playlist_info* playlist,
+                       const char* dir, const char* file,
                        void* index_buffer, int index_buffer_size,
                        void* temp_buffer, int temp_buffer_size)
 {
@@ -1897,7 +1898,7 @@ void playlist_close(struct playlist_info* playlist)
  * Insert track into playlist at specified position (or one of the special
  * positions).  Returns position where track was inserted or -1 if error.
  */
-int playlist_insert_track(struct playlist_info* playlist, char *filename,
+int playlist_insert_track(struct playlist_info* playlist, const char *filename,
                           int position, bool queue)
 {
     int result;
@@ -1925,8 +1926,9 @@ int playlist_insert_track(struct playlist_info* playlist, char *filename,
 /*
  * Insert all tracks from specified directory into playlist.
  */
-int playlist_insert_directory(struct playlist_info* playlist, char *dirname,
-                              int position, bool queue, bool recurse)
+int playlist_insert_directory(struct playlist_info* playlist,
+                              const char *dirname, int position, bool queue,
+                              bool recurse)
 {
     int count = 0;
     int result;
@@ -2226,7 +2228,7 @@ int playlist_sort(struct playlist_info* playlist, bool start_current)
 }
 
 /* returns true if playlist has been modified */
-bool playlist_modified(struct playlist_info* playlist)
+bool playlist_modified(const struct playlist_info* playlist)
 {
     if (!playlist)
         playlist = &current_playlist;
@@ -2240,7 +2242,7 @@ bool playlist_modified(struct playlist_info* playlist)
 }
 
 /* returns index of first track in playlist */
-int playlist_get_first_index(struct playlist_info* playlist)
+int playlist_get_first_index(const struct playlist_info* playlist)
 {
     if (!playlist)
         playlist = &current_playlist;
@@ -2249,7 +2251,7 @@ int playlist_get_first_index(struct playlist_info* playlist)
 }
 
 /* returns shuffle seed of playlist */
-int playlist_get_seed(struct playlist_info* playlist)
+int playlist_get_seed(const struct playlist_info* playlist)
 {
     if (!playlist)
         playlist = &current_playlist;
@@ -2258,7 +2260,7 @@ int playlist_get_seed(struct playlist_info* playlist)
 }
 
 /* returns number of tracks in playlist (includes queued/inserted tracks) */
-int playlist_amount_ex(struct playlist_info* playlist)
+int playlist_amount_ex(const struct playlist_info* playlist)
 {
     if (!playlist)
         playlist = &current_playlist;
@@ -2267,7 +2269,8 @@ int playlist_amount_ex(struct playlist_info* playlist)
 }
 
 /* returns full path of playlist (minus extension) */
-char *playlist_name(struct playlist_info* playlist, char *buf, int buf_size)
+char *playlist_name(const struct playlist_info* playlist, char *buf,
+                    int buf_size)
 {
     char *sep;
 
@@ -2288,7 +2291,7 @@ char *playlist_name(struct playlist_info* playlist, char *buf, int buf_size)
 }
 
 /* returns the playlist filename */
-char *playlist_get_name(struct playlist_info* playlist, char *buf,
+char *playlist_get_name(const struct playlist_info* playlist, char *buf,
                         int buf_size)
 {
     if (!playlist)
diff --git a/apps/playlist.h b/apps/playlist.h
index 482cecd128..8698981d26 100644
--- a/apps/playlist.h
+++ b/apps/playlist.h
@@ -68,9 +68,9 @@ struct playlist_track_info
 
 /* Exported functions only for current playlist. */
 void playlist_init(void);
-int playlist_create(char *dir, char *file);
+int playlist_create(const char *dir, const char *file);
 int playlist_resume(void);
-int playlist_add(char *filename);
+int playlist_add(const char *filename);
 int playlist_shuffle(int random_seed, int start_index);
 int playlist_start(int start_index, int offset);
 bool playlist_check(int steps);
@@ -82,15 +82,17 @@ int playlist_amount(void);
 
 /* Exported functions for all playlists.  Pass NULL for playlist_info
    structure to work with current playlist. */
-int playlist_create_ex(struct playlist_info* playlist, char* dir, char* file,
+int playlist_create_ex(struct playlist_info* playlist,
+                       const char* dir, const char* file,
                        void* index_buffer, int index_buffer_size,
                        void* temp_buffer, int temp_buffer_size);
 int playlist_set_current(struct playlist_info* playlist);
 void playlist_close(struct playlist_info* playlist);
-int playlist_insert_track(struct playlist_info* playlist, char *filename,
+int playlist_insert_track(struct playlist_info* playlist, const char *filename,
                           int position, bool queue);
-int playlist_insert_directory(struct playlist_info* playlist, char *dirname,
-                              int position, bool queue, bool recurse);
+int playlist_insert_directory(struct playlist_info* playlist,
+                              const char *dirname, int position, bool queue,
+                              bool recurse);
 int playlist_insert_playlist(struct playlist_info* playlist, char *filename,
                              int position, bool queue);
 int playlist_delete(struct playlist_info* playlist, int index);
@@ -98,12 +100,13 @@ int playlist_move(struct playlist_info* playlist, int index, int new_index);
 int playlist_randomise(struct playlist_info* playlist, unsigned int seed,
                        bool start_current);
 int playlist_sort(struct playlist_info* playlist, bool start_current);
-bool playlist_modified(struct playlist_info* playlist);
-int playlist_get_first_index(struct playlist_info* playlist);
-int playlist_get_seed(struct playlist_info* playlist);
-int playlist_amount_ex(struct playlist_info* playlist);
-char *playlist_name(struct playlist_info* playlist, char *buf, int buf_size);
-char *playlist_get_name(struct playlist_info* playlist, char *buf,
+bool playlist_modified(const struct playlist_info* playlist);
+int playlist_get_first_index(const struct playlist_info* playlist);
+int playlist_get_seed(const struct playlist_info* playlist);
+int playlist_amount_ex(const struct playlist_info* playlist);
+char *playlist_name(const struct playlist_info* playlist, char *buf,
+                    int buf_size);
+char *playlist_get_name(const struct playlist_info* playlist, char *buf,
                         int buf_size);
 int playlist_get_track_info(struct playlist_info* playlist, int index,
                             struct playlist_track_info* info);
diff --git a/apps/playlist_viewer.c b/apps/playlist_viewer.c
index e5d95495fa..f093efd172 100644
--- a/apps/playlist_viewer.c
+++ b/apps/playlist_viewer.c
@@ -123,8 +123,8 @@ static bool initialize(char* filename, bool reload);
 static void load_playlist_entries(int start_index);
 static void load_playlist_entries_r(int end_index);
 static int  load_entry(int index, int pos, char* p, int size);
-static void format_name(char* dest, char* src);
-static void format_line(struct playlist_entry* track, char* str, int len);
+static void format_name(char* dest, const char* src);
+static void format_line(const struct playlist_entry* track, char* str, int len);
 static void display_playlist(void);
 static void update_display_line(int line, bool scroll);
 static void scroll_display(int lines);
@@ -392,7 +392,7 @@ static int load_entry(int index, int pos, char* p, int size)
 }
 
 /* Format trackname for display purposes */
-static void format_name(char* dest, char* src)
+static void format_name(char* dest, const char* src)
 {
     switch (global_settings.playlist_viewer_track_display)
     {
@@ -422,7 +422,7 @@ static void format_name(char* dest, char* src)
 }
 
 /* Format display line */
-static void format_line(struct playlist_entry* track, char* str, int len)
+static void format_line(const struct playlist_entry* track, char* str, int len)
 {
     char name[MAX_PATH];
 
diff --git a/apps/plugin.c b/apps/plugin.c
index f210462815..a7ae34f67e 100644
--- a/apps/plugin.c
+++ b/apps/plugin.c
@@ -261,7 +261,7 @@ static const struct plugin_api rockbox_api = {
     mpeg_get_last_header,
 };
 
-int plugin_load(char* plugin, void* parameter)
+int plugin_load(const char* plugin, void* parameter)
 {
     enum plugin_status (*plugin_start)(struct plugin_api* api, void* param);
     int rc;
diff --git a/apps/plugin.h b/apps/plugin.h
index 53648ad4c7..e8fb25e555 100644
--- a/apps/plugin.h
+++ b/apps/plugin.h
@@ -153,7 +153,7 @@ struct plugin_api {
 #endif
     void (*backlight_on)(void);
     void (*backlight_off)(void);
-    void (*splash)(int ticks, bool center, char *fmt, ...);
+    void (*splash)(int ticks, bool center, const char *fmt, ...);
 
     /* button */
     int (*button_get)(bool block);
@@ -298,7 +298,7 @@ struct plugin_api {
 };
 
 /* defined by the plugin loader (plugin.c) */
-int plugin_load(char* plugin, void* parameter);
+int plugin_load(const char* plugin, void* parameter);
 void* plugin_get_buffer(int *buffer_size);
 void* plugin_get_mp3_buffer(int *buffer_size);
 int plugin_register_timer(int cycles, int prio, void (*timer_callback)(void));
diff --git a/apps/screens.c b/apps/screens.c
index a926063efc..3e30e3e021 100644
--- a/apps/screens.c
+++ b/apps/screens.c
@@ -656,10 +656,10 @@ bool quick_screen(int context, int button)
 #define MAXLINES 2
 #endif
 
-void splash(int ticks,   /* how long the splash is displayed */
-            bool center, /* FALSE means left-justified, TRUE means
-                            horizontal and vertical center */
-            char *fmt,   /* what to say *printf style */
+void splash(int ticks,       /* how long the splash is displayed */
+            bool center,     /* FALSE means left-justified, TRUE means
+                                horizontal and vertical center */
+            const char *fmt, /* what to say *printf style */
             ...)
 {
     char *next;
@@ -813,7 +813,7 @@ void charging_splash(void)
 #ifdef HAVE_LCD_BITMAP
 
 /* little helper function for voice output */
-static void say_time(int cursorpos, struct tm *tm)
+static void say_time(int cursorpos, const struct tm *tm)
 {
     const int unit[] = { UNIT_HOUR, UNIT_MIN, UNIT_SEC, 0, 0, 0 };
     int value = 0;
@@ -850,7 +850,7 @@ static void say_time(int cursorpos, struct tm *tm)
 #define INDEX_X 0
 #define INDEX_Y 1
 #define INDEX_WIDTH 2
-bool set_time_screen(char* string, struct tm *tm)
+bool set_time_screen(const char* string, struct tm *tm)
 {
     bool done = false;
     int button;
diff --git a/apps/screens.h b/apps/screens.h
index b4f293f0ba..a119a9b853 100644
--- a/apps/screens.h
+++ b/apps/screens.h
@@ -31,14 +31,14 @@ int on_screen(void);
 bool quick_screen(const int, const int);
 #endif
 
-void splash(int ticks,  /* how long */
-            bool center, /* FALSE means left-justified, TRUE means
-                            horizontal and vertical center */
-            char *fmt,  /* what to say *printf style */
+void splash(int ticks,       /* how long */
+            bool center,     /* FALSE means left-justified, TRUE means
+                                horizontal and vertical center */
+            const char *fmt, /* what to say *printf style */
             ...);
 
 #ifdef HAVE_RTC
-bool set_time_screen(char* string, struct tm *tm);
+bool set_time_screen(const char* string, struct tm *tm);
 #endif
 
 bool shutdown_screen(void);
diff --git a/apps/settings.c b/apps/settings.c
index 47969d1abe..b469ce6d54 100644
--- a/apps/settings.c
+++ b/apps/settings.c
@@ -339,7 +339,7 @@ static const struct bit_entry hd_bits[] =
 
 /* helper function to extract n (<=32) bits from an arbitrary position */
 static unsigned long get_bits(
-    unsigned long* p, /* the start of the bitfield array */
+    const unsigned long* p, /* the start of the bitfield array */
     unsigned int from, /* bit no. to start reading from */
     unsigned int size) /* how many bits to read */
 {
@@ -418,7 +418,7 @@ static void set_bits(
  * Calculates the checksum for the config block and returns it
  */
 
-static unsigned short calculate_config_checksum(unsigned char* buf)
+static unsigned short calculate_config_checksum(const unsigned char* buf)
 {
     unsigned int i;
     unsigned char cksum[2];
@@ -890,8 +890,8 @@ void set_file(char* filename, char* setting, int maxlen)
 static int load_cfg_table(
     const struct bit_entry* p_table, /* the table which describes the entries */
     int count, /* number of entries in the table, including the first */
-    char* name, /* the item to be searched */
-    char* value, /* the value which got loaded for that item */
+    const char* name, /* the item to be searched */
+    const char* value, /* the value which got loaded for that item */
     int hint) /* position to start looking */
 {
     int i = hint;
@@ -963,7 +963,7 @@ static int load_cfg_table(
 }
 
 
-bool settings_load_config(char* file)
+bool settings_load_config(const char* file)
 {
     int fd;
     char line[128];
@@ -1238,7 +1238,7 @@ void settings_reset(void) {
 
 }
 
-bool set_bool(char* string, bool* variable )
+bool set_bool(const char* string, bool* variable )
 {
     return set_bool_options(string, variable, 
         STR(LANG_SET_BOOL_YES), 
@@ -1256,9 +1256,9 @@ void bool_funcwrapper(int value)
         boolfunction(false);
 }
 
-bool set_bool_options(char* string, bool* variable,
-                      char* yes_str, int yes_voice,
-                      char* no_str, int no_voice,
+bool set_bool_options(const char* string, bool* variable,
+                      const char* yes_str, int yes_voice,
+                      const char* no_str, int no_voice,
                       void (*function)(bool))
 {
     struct opt_items names[] = { {no_str, no_voice}, {yes_str, yes_voice} };
@@ -1270,8 +1270,8 @@ bool set_bool_options(char* string, bool* variable,
     return result;
 }
 
-bool set_int(char* string, 
-             char* unit,
+bool set_int(const char* string,
+             const char* unit,
              int voice_unit,
              int* variable,
              void (*function)(int),
@@ -1391,7 +1391,7 @@ bool set_int(char* string,
    different and bit-incompatible types and can not share the same access
    code. */
 
-bool set_option(char* string, void* variable, enum optiontype type,
+bool set_option(const char* string, void* variable, enum optiontype type,
                 const struct opt_items* options, int numoptions, void (*function)(int))
 {
     bool done = false;
diff --git a/apps/settings.h b/apps/settings.h
index 78f46eaa4f..331e8dc904 100644
--- a/apps/settings.h
+++ b/apps/settings.h
@@ -264,19 +264,19 @@ void settings_apply(void);
 void settings_apply_pm_range(void);
 void settings_display(void);
 
-bool settings_load_config(char* file);
+bool settings_load_config(const char* file);
 bool settings_save_config(void);
-bool set_bool_options(char* string, bool* variable, 
-                      char* yes_str, int yes_voice,
-                      char* no_str, int no_voice,
+bool set_bool_options(const char* string, bool* variable,
+                      const char* yes_str, int yes_voice,
+                      const char* no_str, int no_voice,
                       void (*function)(bool));
 
-bool set_bool(char* string, bool* variable );
-bool set_option(char* string, void* variable, enum optiontype type,
+bool set_bool(const char* string, bool* variable );
+bool set_option(const char* string, void* variable, enum optiontype type,
                 const struct opt_items* options, int numoptions, void (*function)(int));
-bool set_int(char* string, char* unit, int voice_unit, int* variable,
+bool set_int(const char* string, const char* unit, int voice_unit, int* variable,
              void (*function)(int), int step, int min, int max );
-bool set_time_screen(char* string, struct tm *tm);
+bool set_time_screen(const char* string, struct tm *tm);
 int read_line(int fd, char* buffer, int buffer_size);
 void set_file(char* filename, char* setting, int maxlen);
 
diff --git a/apps/sound_menu.c b/apps/sound_menu.c
index bbf1c6c473..a037c94084 100644
--- a/apps/sound_menu.c
+++ b/apps/sound_menu.c
@@ -42,7 +42,7 @@ static const char* const fmt[] =
     "%d.%02d %s  "      /* 2 decimals */
 };
 
-bool set_sound(char* string, 
+bool set_sound(const char* string,
                int* variable,
                int setting)
 {
diff --git a/apps/status.c b/apps/status.c
index 8c4a7ef809..f144adebef 100644
--- a/apps/status.c
+++ b/apps/status.c
@@ -268,7 +268,7 @@ void status_draw(bool force_redraw)
 }
 
 #ifdef HAVE_LCD_BITMAP
-static void draw_buttonbar_btn(int num, char* caption)
+static void draw_buttonbar_btn(int num, const char* caption)
 {
     int xpos, ypos, button_width, text_width;
     int fw, fh;
@@ -294,7 +294,8 @@ static char stored_caption1[8];
 static char stored_caption2[8];
 static char stored_caption3[8];
 
-void buttonbar_set(char* caption1, char *caption2, char *caption3)
+void buttonbar_set(const char* caption1, const char *caption2,
+                   const char *caption3)
 {
     buttonbar_unset();
     if(caption1)
diff --git a/apps/status.h b/apps/status.h
index c812b9cb75..ab8939cda5 100644
--- a/apps/status.h
+++ b/apps/status.h
@@ -34,7 +34,8 @@ void status_init(void);
 void status_set_ffmode(enum playmode mode);
 #ifdef HAVE_LCD_BITMAP
 bool statusbar(bool state);
-void buttonbar_set(char* caption1, char* caption2, char* caption3);
+void buttonbar_set(const char* caption1, const char* caption2, 
+                   const char* caption3);
 void buttonbar_unset(void);
 bool buttonbar_isset(void);
 void buttonbar_draw(void);
diff --git a/apps/talk.c b/apps/talk.c
index 1b3dda39ed..d90d23866e 100644
--- a/apps/talk.c
+++ b/apps/talk.c
@@ -378,7 +378,7 @@ int talk_id(int id, bool enqueue)
 
 
 /* play a thumbnail from file */
-int talk_file(char* filename, bool enqueue)
+int talk_file(const char* filename, bool enqueue)
 {
     int fd;
     int size;
@@ -532,7 +532,7 @@ int talk_value(int n, int unit, bool enqueue)
 }
 
 /* spell a string */
-int talk_spell(char* spell, bool enqueue) 
+int talk_spell(const char* spell, bool enqueue) 
 {
     char c; /* currently processed char */
     
diff --git a/apps/talk.h b/apps/talk.h
index de93b1678c..c4c8bc7285 100644
--- a/apps/talk.h
+++ b/apps/talk.h
@@ -49,7 +49,7 @@ enum {
 
 /* make a "talkable" ID from number + unit
    unit is upper 4 bits, number the remaining (in regular 2's complement) */
-#define TALK_ID(n,u) ((u)<<UNIT_SHIFT | ((n) & ~(-1<<UNIT_SHIFT))) 
+#define TALK_ID(n,u) ((u)<<UNIT_SHIFT | ((n) & ~(-1<<UNIT_SHIFT)))
 
 /* convenience macro to have both virtual pointer and ID as arguments */
 #define STR(id) ID2P(id), id
@@ -61,9 +61,9 @@ extern const char* const dir_thumbnail_name;
 void talk_init(void);
 int talk_buffer_steal(void); /* claim the mp3 buffer e.g. for play/record */
 int talk_id(int id, bool enqueue); /* play a voice ID from voicefont */
-int talk_file(char* filename, bool enqueue); /* play a thumbnail from file */
+int talk_file(const char* filename, bool enqueue); /* play a thumbnail from file */
 int talk_number(int n, bool enqueue); /* say a number */
 int talk_value(int n, int unit, bool enqueue); /* say a numeric value */
-int talk_spell(char* spell, bool enqueue); /* spell a string */
+int talk_spell(const char* spell, bool enqueue); /* spell a string */
 
 #endif /* __TALK_H__ */
diff --git a/apps/tree.c b/apps/tree.c
index 017e9877f1..c9249caa7d 100644
--- a/apps/tree.c
+++ b/apps/tree.c
@@ -118,7 +118,7 @@ static int boot_cluster;
 static bool boot_changed = false;
 
 static bool start_wps = false;
-static bool dirbrowse(char *root, int *dirfilter);
+static bool dirbrowse(const char *root, const int *dirfilter);
 
 void browse_root(void)
 {
@@ -293,7 +293,7 @@ static int compare(const void* p1, const void* p2)
     return 0; /* never reached */
 }
 
-static void showfileline(int line, int direntry, bool scroll, int *dirfilter)
+static void showfileline(int line, int direntry, bool scroll, const int *dirfilter)
 {
     char* name = dircache[direntry].name;
     int xpos = LINE_X;
@@ -331,7 +331,7 @@ static void showfileline(int line, int direntry, bool scroll, int *dirfilter)
 }
 
 /* load sorted directory into dircache.  returns NULL on failure. */
-struct entry* load_and_sort_directory(char *dirname, int *dirfilter,
+struct entry* load_and_sort_directory(const char *dirname, const int *dirfilter,
                                       int *num_files, bool *buffer_full)
 {
     int i;
@@ -453,7 +453,7 @@ static int recalc_screen_height(void)
 }
 #endif
 
-static int showdir(char *path, int start, int *dirfilter)
+static int showdir(const char *path, int start, const int *dirfilter)
 {
     int i;
     int tree_max_on_screen;
@@ -652,7 +652,7 @@ static bool ask_resume(bool ask_once)
 }
 
 /* load tracks from specified directory to resume play */
-void resume_directory(char *dir)
+void resume_directory(const char *dir)
 {
     bool buffer_full;
 
@@ -753,7 +753,8 @@ void set_current_file(char *path)
 }
 
 #ifdef BUTTON_ON
-static bool handle_on(int *ds, int *dc, int numentries, int tree_max_on_screen, int *dirfilter)
+static bool handle_on(int *ds, int *dc, int numentries, int tree_max_on_screen,
+                      const int *dirfilter)
 {
     bool exit = false;
     bool used = false;
@@ -878,7 +879,7 @@ static bool handle_on(int *ds, int *dc, int numentries, int tree_max_on_screen,
 }
 #endif
 
-static bool dirbrowse(char *root, int *dirfilter)
+static bool dirbrowse(const char *root, const int *dirfilter)
 {
     int numentries=0;
     char buf[MAX_PATH];
@@ -1643,7 +1644,7 @@ bool create_playlist(void)
     return true;
 }
 
-bool rockbox_browse(char *root, int dirfilter)
+bool rockbox_browse(const char *root, int dirfilter)
 {
     bool rc;
     int dircursor_save = dircursor;
diff --git a/apps/tree.h b/apps/tree.h
index 0889b7211e..5a618a8bc3 100644
--- a/apps/tree.h
+++ b/apps/tree.h
@@ -52,12 +52,12 @@ void tree_get_filetypes(const struct filetype**, int*);
 void tree_init(void);
 void browse_root(void);
 void set_current_file(char *path);
-bool rockbox_browse(char *root, int dirfilter);
+bool rockbox_browse(const char *root, int dirfilter);
 bool create_playlist(void);
-void resume_directory(char *dir);
+void resume_directory(const char *dir);
 char *getcwd(char *buf, int size);
 void reload_directory(void);
-struct entry* load_and_sort_directory(char *dirname, int *dirfilter,
+struct entry* load_and_sort_directory(const char *dirname, const int *dirfilter,
                                       int *num_files, bool *buffer_full);
 
 #endif
diff --git a/apps/wps-display.c b/apps/wps-display.c
index 9f136ffa0c..159f0abda6 100644
--- a/apps/wps-display.c
+++ b/apps/wps-display.c
@@ -68,9 +68,11 @@
 #ifdef HAVE_LCD_CHARCELLS
 static unsigned char wps_progress_pat[8]={0,0,0,0,0,0,0,0};
 static bool full_line_progressbar=0;
-static bool draw_player_progress(struct mp3entry* id3, int ff_rewwind_count);
+static bool draw_player_progress(const struct mp3entry* id3,
+                                 int ff_rewwind_count);
 static void draw_player_fullbar(char* buf, int buf_size,
-                                struct mp3entry* id3, int ff_rewwind_count);
+                                const struct mp3entry* id3,
+                                int ff_rewwind_count);
 static char map_fullbar_char(char ascii_val);
 #endif
 
@@ -86,7 +88,7 @@ bool wps_time_countup = true;
 static bool wps_loaded = false;
 
 /* Set format string to use for WPS, splitting it into lines */
-static void wps_format(char* fmt)
+static void wps_format(const char* fmt)
 {
     char* buf = format_buffer;
     char* start_of_line = format_buffer;
@@ -170,7 +172,7 @@ void wps_reset(void)
     memset(&format_buffer, 0, sizeof format_buffer);
 }
 
-bool wps_load(char* file, bool display)
+bool wps_load(const char* file, bool display)
 {
     int i, s;
     char buffer[FORMAT_BUFFER_SIZE];
@@ -256,10 +258,10 @@ static void format_time(char* buf, int buf_size, int time)
  *
  * Returns buf if the desired level was found, NULL otherwise.
  */
-static char* get_dir(char* buf, int buf_size, char* path, int level)
+static char* get_dir(char* buf, int buf_size, const char* path, int level)
 {
-    char* sep;
-    char* last_sep;
+    const char* sep;
+    const char* last_sep;
     int len;
 
     sep = path + strlen(path);
@@ -304,7 +306,7 @@ static char* get_dir(char* buf, int buf_size, char* path, int level)
  */
 static char* get_tag(struct mp3entry* cid3,
                      struct mp3entry* nid3,
-                     char* tag,
+                     const char* tag,
                      char* buf,
                      int buf_size,
                      unsigned char* tag_len,
@@ -622,7 +624,7 @@ static char* get_tag(struct mp3entry* cid3,
  *
  * Returns the new position in fmt.
  */
-static char* skip_conditional(char* fmt, bool to_else)
+static const char* skip_conditional(const char* fmt, bool to_else)
 {
     int level = 1;
 
@@ -693,7 +695,7 @@ static void format_display(char* buf,
                            int buf_size,
                            struct mp3entry* id3,
                            struct mp3entry* nid3, /* next song's id3 */
-                           char* fmt,
+                           const char* fmt,
                            unsigned char* subline_time_mult,
                            unsigned char* flags)
 {
@@ -1051,7 +1053,8 @@ bool wps_display(struct mp3entry* id3,
 }
 
 #ifdef HAVE_LCD_CHARCELLS
-static bool draw_player_progress(struct mp3entry* id3, int ff_rewwind_count)
+static bool draw_player_progress(const struct mp3entry* id3,
+                                 int ff_rewwind_count)
 {
     char player_progressbar[7];
     char binline[36];
@@ -1087,7 +1090,8 @@ static bool draw_player_progress(struct mp3entry* id3, int ff_rewwind_count)
 }
 
 static void draw_player_fullbar(char* buf, int buf_size,
-                                struct mp3entry* id3, int ff_rewwind_count)
+                                const struct mp3entry* id3,
+                                int ff_rewwind_count)
 {
     int i,j,lcd_char_pos;
 
diff --git a/apps/wps-display.h b/apps/wps-display.h
index 7e5df59b5e..7f7976370a 100644
--- a/apps/wps-display.h
+++ b/apps/wps-display.h
@@ -36,8 +36,7 @@
 bool wps_refresh(struct mp3entry* id3, struct mp3entry* nid3,
                  int ffwd_offset, unsigned char refresh_mode);
 bool wps_display(struct mp3entry* id3, struct mp3entry* nid3);
-bool wps_load(char* file, bool display);
+bool wps_load(const char* file, bool display);
 void wps_reset(void);
-char* wps_get_genre(struct mp3entry* id3);
 
 #endif