diff --git a/apps/playback.c b/apps/playback.c
index 3fa42b9f94..7b614cd0d0 100644
--- a/apps/playback.c
+++ b/apps/playback.c
@@ -1562,11 +1562,12 @@ static void buffering_handle_rebuffer_callback(void *data)
     queue_post(&audio_queue, Q_AUDIO_FLUSH, 0);
 }
 
-static void buffering_handle_finished_callback(int *data)
+static void buffering_handle_finished_callback(void *data)
 {
     logf("handle %d finished buffering", *data);
+    int hid = (*(int*)data);
 
-    if (*data == tracks[track_widx].id3_hid)
+    if (hid == tracks[track_widx].id3_hid)
     {
         int offset = ci.new_track + wps_offset;
         int next_idx = (track_ridx + offset + 1) & MAX_TRACK_MASK;
@@ -1574,16 +1575,16 @@ static void buffering_handle_finished_callback(int *data)
            We can ask the audio thread to load the rest of the track's data. */
         LOGFQUEUE("audio >| audio Q_AUDIO_FINISH_LOAD");
         queue_post(&audio_queue, Q_AUDIO_FINISH_LOAD, 0);
-        if (tracks[next_idx].id3_hid == *data)
+        if (tracks[next_idx].id3_hid == hid)
             send_event(PLAYBACK_EVENT_NEXTTRACKID3_AVAILABLE, NULL);
     }
     else
     {
         /* This is most likely an audio handle, so we strip the useless
            trailing tags that are left. */
-        strip_tags(*data);
+        strip_tags(hid);
 
-        if (*data == tracks[track_widx-1].audio_hid
+        if (hid == tracks[track_widx-1].audio_hid
             && filling == STATE_END_OF_PLAYLIST)
         {
             /* This was the last track in the playlist.
diff --git a/apps/playlist.c b/apps/playlist.c
index b70fdc8a1f..1e96ebf46b 100644
--- a/apps/playlist.c
+++ b/apps/playlist.c
@@ -1214,8 +1214,9 @@ static int compare(const void* p1, const void* p2)
  * without affecting playlist load up performance.  This thread also flushes
  * any pending control commands when the disk spins up.
  */
-static bool playlist_flush_callback(void)
+static void playlist_flush_callback(void *param)
 {
+    (void)param;
     struct playlist_info *playlist;
     playlist = &current_playlist;
     if (playlist->control_fd >= 0)
@@ -1228,7 +1229,6 @@ static bool playlist_flush_callback(void)
         }
         sync_control(playlist, true);
     }
-    return true;
 }
          
 static void playlist_thread(void)
diff --git a/apps/plugin.h b/apps/plugin.h
index 41375a6adb..6ff7e7e568 100644
--- a/apps/plugin.h
+++ b/apps/plugin.h
@@ -403,8 +403,8 @@ struct plugin_api {
     void (*storage_spin)(void);
     void (*storage_spindown)(int seconds);
 #if USING_STORAGE_CALLBACK
-    void (*register_storage_idle_func)(storage_idle_notify function);
-    void (*unregister_storage_idle_func)(storage_idle_notify function, bool run);
+    void (*register_storage_idle_func)(void (*function)(void *data));
+    void (*unregister_storage_idle_func)(void (*function)(void *data), bool run);
 #endif /* USING_STORAGE_CALLBACK */
     void (*reload_directory)(void);
     char *(*create_numbered_filename)(char *buffer, const char *path,
diff --git a/apps/plugins/battery_bench.c b/apps/plugins/battery_bench.c
index 909de03512..c0b6d44e9f 100644
--- a/apps/plugins/battery_bench.c
+++ b/apps/plugins/battery_bench.c
@@ -306,22 +306,19 @@ static unsigned int charge_state(void)
 #endif
 
 
-static bool flush_buffer(void)
+static void flush_buffer(void* data)
 {
+    (void)data;
     int fd, secs;
     unsigned int i;
 
     /* don't access the disk when in usb mode, or when no data is available */
     if (in_usb_mode || (buf_idx == 0))
-    {
-        return false;
-    }
+        return;
 
     fd = rb->open(BATTERY_LOG, O_RDWR | O_CREAT | O_APPEND);
     if (fd < 0)
-    {
-        return false;
-    }
+        return;
 
     for (i = 0; i < buf_idx; i++)
     {
@@ -357,7 +354,6 @@ static bool flush_buffer(void)
     rb->close(fd);
 
     buf_idx = 0;
-    return true;
 }
 
 
@@ -395,7 +391,7 @@ void thread(void)
            for this to occur because it requires > 16 hours of no disk activity.
          */
         if (buf_idx == BUF_ELEMENTS) {
-            flush_buffer();
+            flush_buffer(NULL);
         }
         
         /* sleep some time until next measurement */
diff --git a/apps/scrobbler.c b/apps/scrobbler.c
index b0f65158e8..83f546b59f 100644
--- a/apps/scrobbler.c
+++ b/apps/scrobbler.c
@@ -128,11 +128,11 @@ static void write_cache(void)
     cache_pos = 0;
 }
 
-static bool scrobbler_flush_callback(void)
+static void scrobbler_flush_callback(void *data)
 {
+    (void)data;
     if (scrobbler_initialised && cache_pos)
         write_cache();
-    return true;
 }
 
 static void add_to_cache(unsigned long play_length)
@@ -185,8 +185,9 @@ static void add_to_cache(unsigned long play_length)
 
 }
 
-void scrobbler_change_event(struct mp3entry *id)
+static void scrobbler_change_event(void *data)
 {
+    struct mp3entry *id = (struct mp3entry*)data;
     /* add entry using the previous scrobbler_entry and timestamp */
     if (pending)
         add_to_cache(audio_prev_elapsed());
diff --git a/apps/scrobbler.h b/apps/scrobbler.h
index d7a9b25624..050522e43b 100644
--- a/apps/scrobbler.h
+++ b/apps/scrobbler.h
@@ -18,10 +18,14 @@
  * KIND, either express or implied.
  *
  ****************************************************************************/
- 
-void scrobbler_change_event(struct mp3entry *id);
+
+#ifndef __SCROBBLER_H__
+#define __SCROBBLER_H__
+
 int scrobbler_init(void);
 void scrobbler_flush_cache(void);
 void scrobbler_shutdown(void);
 void scrobbler_poweroff(void);
 bool scrobbler_is_enabled(void);
+
+#endif /* __SCROBBLER_H__ */
diff --git a/apps/settings.c b/apps/settings.c
index 7a36a0ee1d..f12bd92bfd 100644
--- a/apps/settings.c
+++ b/apps/settings.c
@@ -568,17 +568,17 @@ static bool settings_write_config(const char* filename, int options)
     return true;
 }
 #ifndef HAVE_RTC_RAM
-static bool flush_global_status_callback(void)
+static void flush_global_status_callback(void *data)
 {
-    return write_nvram_data(nvram_buffer,NVRAM_BLOCK_SIZE);
+    (void)data;
+    write_nvram_data(nvram_buffer,NVRAM_BLOCK_SIZE);
 }
 #endif
-static bool flush_config_block_callback(void)
+static void flush_config_block_callback(void *data)
 {
-    bool r1, r2;
-    r1 = write_nvram_data(nvram_buffer,NVRAM_BLOCK_SIZE);
-    r2 = settings_write_config(CONFIGFILE, SETTINGS_SAVE_CHANGED);
-    return r1 || r2;
+    (void)data;
+    write_nvram_data(nvram_buffer,NVRAM_BLOCK_SIZE);
+    settings_write_config(CONFIGFILE, SETTINGS_SAVE_CHANGED);
 }
 
 /*
diff --git a/apps/tagcache.c b/apps/tagcache.c
index a5df2f0ad1..14d88bbfb8 100644
--- a/apps/tagcache.c
+++ b/apps/tagcache.c
@@ -3068,16 +3068,16 @@ static bool command_queue_is_full(void)
     return (next == command_queue_ridx);
 }
 
-static bool command_queue_sync_callback(void)
+static void command_queue_sync_callback(void *data)
 {
-    
+    (void)data;
     struct master_header myhdr;
     int masterfd;
         
     mutex_lock(&command_queue_mutex);
 	
     if ( (masterfd = open_master_fd(&myhdr, true)) < 0)
-        return false;
+        return;
     
     while (command_queue_ridx != command_queue_widx)
     {
@@ -3092,7 +3092,7 @@ static bool command_queue_sync_callback(void)
                 
                 /* Re-open the masterfd. */
                 if ( (masterfd = open_master_fd(&myhdr, true)) < 0)
-                    return true;
+                    return;
                 
                 break;
             }
@@ -3111,7 +3111,6 @@ static bool command_queue_sync_callback(void)
     
     tc_stat.queue_length = 0;
     mutex_unlock(&command_queue_mutex);
-    return true;
 }
 
 static void run_command_queue(bool force)
@@ -3120,7 +3119,7 @@ static void run_command_queue(bool force)
         return;
     
     if (force || command_queue_is_full())
-        command_queue_sync_callback();
+        command_queue_sync_callback(NULL);
     else
         register_storage_idle_func(command_queue_sync_callback);
 }
diff --git a/apps/tagtree.c b/apps/tagtree.c
index 2962d57dac..832a49e359 100644
--- a/apps/tagtree.c
+++ b/apps/tagtree.c
@@ -642,9 +642,10 @@ static int compare(const void *p1, const void *p2)
     return strncasecmp(e1->name, e2->name, MAX_PATH);
 }
 
-static void tagtree_buffer_event(struct mp3entry *id3)
+static void tagtree_buffer_event(void *data)
 {
     struct tagcache_search tcs;
+    struct mp3entry *id3 = (struct mp3entry*)data;
     
     /* Do not gather data unless proper setting has been enabled. */
     if (!global_settings.runtimedb)
@@ -671,12 +672,13 @@ static void tagtree_buffer_event(struct mp3entry *id3)
     tagcache_search_finish(&tcs);
 }
 
-static void tagtree_track_finish_event(struct mp3entry *id3)
+static void tagtree_track_finish_event(void *data)
 {
     long playcount;
     long playtime;
     long lastplayed;
     long tagcache_idx;
+    struct mp3entry *id3 = (struct mp3entry*)data;
     
     /* Do not gather data unless proper setting has been enabled. */
     if (!global_settings.runtimedb)
diff --git a/firmware/ata_idle_notify.c b/firmware/ata_idle_notify.c
index 99b1d4d786..35d192bee0 100644
--- a/firmware/ata_idle_notify.c
+++ b/firmware/ata_idle_notify.c
@@ -25,12 +25,12 @@
 #include "kernel.h"
 #include "string.h"
 
-void register_storage_idle_func(storage_idle_notify function)
+void register_storage_idle_func(void (*function)(void *data))
 {
 #if USING_STORAGE_CALLBACK
     add_event(DISK_EVENT_SPINUP, true, function);
 #else
-    function(); /* just call the function now */
+    function(NULL); /* just call the function now */
 /* this _may_ cause problems later if the calling function
    sets a variable expecting the callback to unset it, because
    the callback will be run before this function exits, so before the var is set */
@@ -38,12 +38,12 @@ void register_storage_idle_func(storage_idle_notify function)
 }
 
 #if USING_STORAGE_CALLBACK
-void unregister_storage_idle_func(storage_idle_notify func, bool run)
+void unregister_storage_idle_func(void (*func)(void *data), bool run)
 {
     remove_event(DISK_EVENT_SPINUP, func);
     
     if (run)
-        func();
+        func(NULL);
 }
 
 bool call_storage_idle_notifys(bool force)
diff --git a/firmware/events.c b/firmware/events.c
index 951214377e..dca612bc7b 100644
--- a/firmware/events.c
+++ b/firmware/events.c
@@ -33,7 +33,7 @@ struct sysevent {
 
 static struct sysevent events[MAX_SYS_EVENTS];
 
-bool add_event(unsigned short id, bool oneshot, void (*handler))
+bool add_event(unsigned short id, bool oneshot, void (*handler)(void *data))
 {
     int i;
     
@@ -60,7 +60,7 @@ bool add_event(unsigned short id, bool oneshot, void (*handler))
     return false;
 }
 
-void remove_event(unsigned short id, void (*handler))
+void remove_event(unsigned short id, void (*handler)(void *data))
 {
     int i;
     
diff --git a/firmware/export/ata_idle_notify.h b/firmware/export/ata_idle_notify.h
index 18f1648e00..348165f1d1 100644
--- a/firmware/export/ata_idle_notify.h
+++ b/firmware/export/ata_idle_notify.h
@@ -48,11 +48,9 @@ enum {
                                && (CONFIG_NAND == NAND_IFP7XX)) \
                             && !defined(BOOTLOADER)
 
-typedef bool (*storage_idle_notify)(void);
-
-extern void register_storage_idle_func(storage_idle_notify function);
+extern void register_storage_idle_func(void (*function)(void *data));
 #if USING_STORAGE_CALLBACK
-extern void unregister_storage_idle_func(storage_idle_notify function, bool run);
+extern void unregister_storage_idle_func(void (*function)(void *data), bool run);
 extern bool call_storage_idle_notifys(bool force);
 #else
 #define unregister_storage_idle_func(f,r)
diff --git a/firmware/export/events.h b/firmware/export/events.h
index cad0fad895..694566a43e 100644
--- a/firmware/export/events.h
+++ b/firmware/export/events.h
@@ -38,8 +38,8 @@
 #define EVENT_CLASS_BUFFERING  0x0400
 #define EVENT_CLASS_GUI        0x0800
 
-bool add_event(unsigned short id, bool oneshot, void (*handler));
-void remove_event(unsigned short id, void (*handler));
+bool add_event(unsigned short id, bool oneshot, void (*handler)(void *data));
+void remove_event(unsigned short id, void (*handler)(void *data));
 void send_event(unsigned short id, void *data);
 
 #endif