diff --git a/firmware/common/dir.c b/firmware/common/dir.c
index f89129ae34..245947b134 100644
--- a/firmware/common/dir.c
+++ b/firmware/common/dir.c
@@ -26,6 +26,7 @@
 #include "debug.h"
 #include "dir.h"
 #include "pathfuncs.h"
+#include "timefuncs.h"
 #include "fileobj_mgr.h"
 #include "dircache_redirect.h"
 
@@ -406,7 +407,7 @@ struct dirinfo dir_get_info(DIR *dirp, struct dirent *entry)
     {
         .attribute = entry->info.attr,
         .size      = entry->info.size,
-        .mtime     = fattime_mktime(entry->info.wrtdate, entry->info.wrttime),
+        .mtime     = dostime_mktime(entry->info.wrtdate, entry->info.wrttime),
     };
 
 file_error:
diff --git a/firmware/common/dircache.c b/firmware/common/dircache.c
index 589986911c..3b880d3382 100644
--- a/firmware/common/dircache.c
+++ b/firmware/common/dircache.c
@@ -2956,7 +2956,7 @@ void dircache_dump(void)
         FOR_EACH_CACHE_ENTRY(ce)
         {
         #ifdef DIRCACHE_NATIVE
-            time_t mtime = fattime_mktime(ce->wrtdate, ce->wrttime);
+            time_t mtime = dostime_mktime(ce->wrtdate, ce->wrttime);
         #else
             time_t mtime = ce->mtime;
         #endif
diff --git a/firmware/common/timefuncs.c b/firmware/common/timefuncs.c
index 108431753a..d87e6b67f2 100644
--- a/firmware/common/timefuncs.c
+++ b/firmware/common/timefuncs.c
@@ -32,6 +32,20 @@
 
 static struct tm tm;
 
+time_t dostime_mktime(uint16_t dosdate, uint16_t dostime)
+{
+    /* this knows our mktime() only uses these struct tm fields */
+    struct tm tm;
+    tm.tm_sec  = ((dostime      ) & 0x1f) * 2;
+    tm.tm_min  = ((dostime >>  5) & 0x3f);
+    tm.tm_hour = ((dostime >> 11)       );
+    tm.tm_mday = ((dosdate      ) & 0x1f);
+    tm.tm_mon  = ((dosdate >>  5) & 0x0f) - 1;
+    tm.tm_year = ((dosdate >>  9)       ) + 80;
+
+    return mktime(&tm);
+}
+
 #if !CONFIG_RTC
 static inline bool rtc_dirty(void)
 {
diff --git a/firmware/drivers/fat.c b/firmware/drivers/fat.c
index 337e29a1bc..cc9735d0f7 100644
--- a/firmware/drivers/fat.c
+++ b/firmware/drivers/fat.c
@@ -2954,20 +2954,6 @@ void fat_empty_fat_direntry(struct fat_direntry *entry)
     entry->firstcluster = 0;
 }
 
-time_t fattime_mktime(uint16_t fatdate, uint16_t fattime)
-{
-    /* this knows our mktime() only uses these struct tm fields */
-    struct tm tm;
-    tm.tm_sec  = ((fattime      ) & 0x1f) * 2;
-    tm.tm_min  = ((fattime >>  5) & 0x3f);
-    tm.tm_hour = ((fattime >> 11)       );
-    tm.tm_mday = ((fatdate      ) & 0x1f);
-    tm.tm_mon  = ((fatdate >>  5) & 0x0f) - 1;
-    tm.tm_year = ((fatdate >>  9)       ) + 80;
-
-    return mktime(&tm);
-}
-
 void fat_init(void)
 {
     dc_lock_cache();
diff --git a/firmware/export/fat.h b/firmware/export/fat.h
index b8092290e6..27c2a161f6 100644
--- a/firmware/export/fat.h
+++ b/firmware/export/fat.h
@@ -174,7 +174,6 @@ void fat_recalc_free(IF_MV_NONVOID(int volume));
 bool fat_size(IF_MV(int volume,) unsigned long *size, unsigned long *free);
 
 /** Misc. **/
-time_t fattime_mktime(uint16_t fatdate, uint16_t fattime);
 void fat_empty_fat_direntry(struct fat_direntry *entry);
 void fat_init(void);
 
diff --git a/firmware/include/timefuncs.h b/firmware/include/timefuncs.h
index c72508e862..2e8ef01ca6 100644
--- a/firmware/include/timefuncs.h
+++ b/firmware/include/timefuncs.h
@@ -24,8 +24,10 @@
 
 #include "config.h"
 #include <stdbool.h>
+#include <stdint.h>
 #include "time.h"
 
+time_t dostime_mktime(uint16_t dosdate, uint16_t dostime);
 struct tm *get_time(void);
 int set_time(const struct tm *tm);
 #if CONFIG_RTC