diff --git a/src/file_frm.c b/src/file_frm.c
index a861fd91..826bd8dc 100644
--- a/src/file_frm.c
+++ b/src/file_frm.c
@@ -45,27 +45,6 @@ const file_hint_t file_hint_frm= {
   .register_header_check=&register_header_check_frm
 };
 
-static const unsigned char frm_header[14]= {
-  '#', 'U', 'G', 'C', ':', '2', ' ', 'D',
-  'W', 'G', 'F', 'O', 'R', 'M'};
-
-static void register_header_check_frm(file_stat_t *file_stat)
-{
-  register_header_check(0, frm_header,sizeof(frm_header), &header_check_frm, file_stat);
-}
-
-static int header_check_frm(const unsigned char *buffer, const unsigned int buffer_size, const unsigned int safe_header_only, const file_recovery_t *file_recovery, file_recovery_t *file_recovery_new)
-{
-  if(memcmp(buffer,frm_header,sizeof(frm_header))==0)
-  {
-    reset_file_recovery(file_recovery_new);
-    file_recovery_new->file_check=file_check_frm;
-    file_recovery_new->extension=file_hint_frm.extension;
-    return 1;
-  }
-  return 0;
-}
-
 static void file_check_frm(file_recovery_t *file_recovery)
 {
   const unsigned char frm_footer[11]= {
@@ -73,3 +52,21 @@ static void file_check_frm(file_recovery_t *file_recovery)
     'U', 'G', 'C'};
   file_search_footer(file_recovery, frm_footer, sizeof(frm_footer), 1);
 }
+
+static int header_check_frm(const unsigned char *buffer, const unsigned int buffer_size, const unsigned int safe_header_only, const file_recovery_t *file_recovery, file_recovery_t *file_recovery_new)
+{
+  if(!isprint(buffer[14]) || !isprint(buffer[15]) || !isprint(buffer[16]) || !isprint(buffer[17]))
+    return 0;
+  reset_file_recovery(file_recovery_new);
+  file_recovery_new->file_check=file_check_frm;
+  file_recovery_new->extension=file_hint_frm.extension;
+  return 1;
+}
+
+static void register_header_check_frm(file_stat_t *file_stat)
+{
+  static const unsigned char frm_header[14]= {
+    '#', 'U', 'G', 'C', ':', '2', ' ', 'D',
+    'W', 'G', 'F', 'O', 'R', 'M'};
+  register_header_check(0, frm_header,sizeof(frm_header), &header_check_frm, file_stat);
+}