3 files changed, 17 insertions, 2 deletions

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)
 {