diff --git a/app/platform/vfs.h b/app/platform/vfs.h
index 5a468255..572d0372 100644
--- a/app/platform/vfs.h
+++ b/app/platform/vfs.h
@@ -85,7 +85,7 @@ inline sint32_t vfs_flush( int fd ) {
 //   Returns: File size
 inline uint32_t vfs_size( int fd ) {
   vfs_file *f = (vfs_file *)fd;
-  return f && f->fns->size ? f->fns->size( f ) : 0;
+  return f ? f->fns->size( f ) : 0;
 }
 
 // vfs_ferrno - get file system specific errno
diff --git a/app/spiffs/spiffs.c b/app/spiffs/spiffs.c
index 1a6a465f..093534fc 100644
--- a/app/spiffs/spiffs.c
+++ b/app/spiffs/spiffs.c
@@ -243,6 +243,7 @@ static sint32_t myspiffs_vfs_lseek( const struct vfs_file *fd, sint32_t off, int
 static sint32_t myspiffs_vfs_eof( const struct vfs_file *fd );
 static sint32_t myspiffs_vfs_tell( const struct vfs_file *fd );
 static sint32_t myspiffs_vfs_flush( const struct vfs_file *fd );
+static uint32_t myspiffs_vfs_size( const struct vfs_file *fd );
 static sint32_t myspiffs_vfs_ferrno( const struct vfs_file *fd );
 
 static sint32_t  myspiffs_vfs_closedir( const struct vfs_dir *dd );
@@ -295,7 +296,7 @@ static vfs_file_fns myspiffs_file_fns = {
   .eof       = myspiffs_vfs_eof,
   .tell      = myspiffs_vfs_tell,
   .flush     = myspiffs_vfs_flush,
-  .size      = NULL,
+  .size      = myspiffs_vfs_size,
   .ferrno    = myspiffs_vfs_ferrno
 };
 
@@ -477,6 +478,16 @@ static sint32_t myspiffs_vfs_flush( const struct vfs_file *fd ) {
   return SPIFFS_fflush( &fs, fh ) >= 0 ? VFS_RES_OK : VFS_RES_ERR;
 }
 
+static uint32_t myspiffs_vfs_size( const struct vfs_file *fd ) {
+  GET_FILE_FH(fd);
+
+  int32_t curpos = SPIFFS_tell( &fs, fh );
+  int32_t size = SPIFFS_lseek( &fs, fh, 0, SPIFFS_SEEK_END );
+  (void) SPIFFS_lseek( &fs, fh, curpos, SPIFFS_SEEK_SET );
+
+   return size;
+}
+
 static sint32_t myspiffs_vfs_ferrno( const struct vfs_file *fd ) {
   return SPIFFS_errno( &fs );
 }