diff --git a/apps/mpeg.c b/apps/mpeg.c
index 514379c16c..eb2cc735ba 100644
--- a/apps/mpeg.c
+++ b/apps/mpeg.c
@@ -131,10 +131,10 @@ static struct trackdata trackdata[MAX_TRACK_ENTRIES];
 
 static unsigned int current_track_counter = 0;
 
-/* Play time of the previous track */
-unsigned long prev_track_elapsed;
-
 #ifndef SIMULATOR
+/* Play time of the previous track */
+static unsigned long prev_track_elapsed;
+
 static int track_read_idx = 0;
 static int track_write_idx = 0;
 #endif /* !SIMULATOR */
@@ -213,10 +213,10 @@ static int prerecord_count;   /* Number of seconds in the prerecord buffer */
 static int prerecord_timeout; /* The tick count of the next prerecord data
                                  store */
 
-unsigned long record_start_time; /* Value of current_tick when recording
-                                    was started */
-unsigned long pause_start_time;  /* Value of current_tick when pause was
-                                    started */
+static unsigned long record_start_time; /* Value of current_tick when recording
+                                           was started */
+static unsigned long pause_start_time;  /* Value of current_tick when pause was
+                                           started */
 static unsigned long last_rec_time;
 static unsigned long num_rec_bytes;
 static unsigned long last_rec_bytes;
diff --git a/apps/tree.c b/apps/tree.c
index 5a8445cacf..dda36903e7 100644
--- a/apps/tree.c
+++ b/apps/tree.c
@@ -84,7 +84,7 @@ struct gui_synclist tree_lists;
 /* I put it here because other files doesn't use it yet,
  * but should be elsewhere since it will be used mostly everywhere */
 #ifdef HAVE_BUTTONBAR
-struct gui_buttonbar tree_buttonbar;
+static struct gui_buttonbar tree_buttonbar;
 #endif
 static struct tree_context tc;
 
diff --git a/firmware/usbstack/usb_hid.c b/firmware/usbstack/usb_hid.c
index 6847d0b45d..905f2f0230 100644
--- a/firmware/usbstack/usb_hid.c
+++ b/firmware/usbstack/usb_hid.c
@@ -168,14 +168,14 @@ typedef struct
     bool is_key_released;
 } usb_hid_report_t;
 
-usb_hid_report_t usb_hid_reports[REPORT_ID_COUNT];
+static usb_hid_report_t usb_hid_reports[REPORT_ID_COUNT];
 
 static unsigned char report_descriptor[HID_BUF_SIZE_REPORT]
     USB_DEVBSS_ATTR __attribute__((aligned(32)));
 
 static unsigned char send_buffer[HID_NUM_BUFFERS][HID_BUF_SIZE_MSG]
     USB_DEVBSS_ATTR __attribute__((aligned(32)));
-size_t send_buffer_len[HID_NUM_BUFFERS];
+static size_t send_buffer_len[HID_NUM_BUFFERS];
 static int cur_buf_prepare;
 static int cur_buf_send;