diff --git a/apps/plugin.h b/apps/plugin.h
index 464a581dab..31c87433e7 100644
--- a/apps/plugin.h
+++ b/apps/plugin.h
@@ -865,7 +865,7 @@ struct plugin_api {
        the API gets incompatible */
 
 #ifdef HAVE_LCD_BITMAP
-    int (*is_diacritic)(const unsigned short char_code, bool *is_rtl);
+    bool (*is_diacritic)(const unsigned short char_code, bool *is_rtl);
 #endif
 };
 
diff --git a/firmware/SOURCES b/firmware/SOURCES
index dd1575a076..719fc80b83 100644
--- a/firmware/SOURCES
+++ b/firmware/SOURCES
@@ -97,7 +97,7 @@ drivers/lcd-16bit-vert.c
 drivers/lcd-16bit.c
 #endif
 #endif /* LCD_DEPTH */
-drivers/diacritic.c
+common/diacritic.c
 #endif /* HAVE_LCD_BITMAP */
 
 #ifdef HAVE_REMOTE_LCD
diff --git a/firmware/drivers/diacritic.c b/firmware/common/diacritic.c
similarity index 99%
rename from firmware/drivers/diacritic.c
rename to firmware/common/diacritic.c
index ff40b195c7..aa2726c5fb 100644
--- a/firmware/drivers/diacritic.c
+++ b/firmware/common/diacritic.c
@@ -193,7 +193,7 @@ static const struct diac_range diac_ranges[] =
 static unsigned short mru_len = 0;
 static unsigned short diacritic_mru[MRU_MAX_LEN];
 
-int is_diacritic(const unsigned short char_code, bool *is_rtl)
+bool is_diacritic(const unsigned short char_code, bool *is_rtl)
 {
     unsigned short mru, i;
     const struct diac_range *diac;
diff --git a/firmware/include/diacritic.h b/firmware/include/diacritic.h
index 052be7f894..52ce6b0646 100644
--- a/firmware/include/diacritic.h
+++ b/firmware/include/diacritic.h
@@ -26,5 +26,5 @@
  * Sets is_rtl (if it's not NULL) to whether the character
  * belongs to an RTL language.
  */
-int is_diacritic(const unsigned short char_code, bool *is_rtl);
+bool is_diacritic(const unsigned short char_code, bool *is_rtl);
 #endif