diff --git a/xorriso/check_media.c b/xorriso/check_media.c
index c1d738e2..0838a26c 100644
--- a/xorriso/check_media.c
+++ b/xorriso/check_media.c
@@ -293,11 +293,12 @@ int Sectorbitmap_from_file(struct SectorbitmaP **o, char *path, char *msg,
  off_t sectors, sector_size;
  ssize_t i, map_size;
  unsigned char *map;
- unsigned char *buf;
+ unsigned char *buf, buf_head[26];
 
  buf= TSOB_FELD(unsigned char, bufsize);
  if(buf == NULL)
    return(-1);
+ buf_head[0]= 0;
 
  *os_errno= 0;
  if(msg != NULL)
@@ -322,10 +323,12 @@ wrong_filetype:;
    }
    ret= 0; goto ex;
  }
- if(strncmp((char *) buf, "xorriso sector bitmap v1        ", 32) == 0)
-   /* ok */;
- else if(strncmp((char *) buf, "xorriso sector bitmap v2 ", 25) == 0 ||
-         strncmp((char *) buf, "xorriso sector bitmap v3 ", 25) == 0) {
+ if(strncmp((char *) buf, "xorriso sector bitmap v1        ", 32) == 0) {
+   memcpy(buf_head, buf, 25);
+ } else if(strncmp((char *) buf, "xorriso sector bitmap v2 ", 25) == 0 ||
+	   strncmp((char *) buf, "xorriso sector bitmap v3 ", 25) == 0) {
+   memcpy(buf_head, buf, 25);
+   buf_head[25]= 0;
    skip= -1;
    sscanf(((char *) buf) + 25, "%d", &skip);
    if(skip < 0)
@@ -340,7 +343,8 @@ wrong_filetype:;
    }
  } else
    {ret= 0; goto wrong_filetype;}
- if(strncmp((char *) buf, "xorriso sector bitmap v2 ", 25) == 0) {
+ if(strncmp((char *) buf_head, "xorriso sector bitmap v1 ", 25) == 0 ||
+    strncmp((char *) buf_head, "xorriso sector bitmap v2 ", 25) == 0) {
    ret= read(fd, buf, 8);
    if(ret < 8)
      goto wrong_filetype;
@@ -354,13 +358,12 @@ wrong_filetype:;
      goto wrong_filetype;
    if((buf[0] & 128) || (buf[8] & 128))
      goto wrong_filetype;
-   /* (My compiler hates off_t = 1 << 32. So i do it by multiplication) */
-   sectors= ((buf[0] << 24) | (buf[1] << 16) | (buf[2] << 8) | buf[3]) *
-            (off_t) 0x100000000;
-   sectors|= (buf[4] << 24) | (buf[5] << 16) | (buf[6] << 8) | buf[7];
-   sector_size= ((buf[8] << 24) | (buf[9] << 16) | (buf[10] << 8) | buf[11]) *
-                (off_t) 0x100000000;
-   sector_size|= (buf[12] << 24) | (buf[13] << 16) | (buf[14] << 8) | buf[15];
+   sectors= ((off_t) buf[0] << 56) | ((off_t) buf[1] << 48) |
+            ((off_t) buf[2] << 40) | ((off_t) buf[3] << 32) |
+            (buf[4] << 24) | (buf[5] << 16) | (buf[6] << 8) | buf[7];
+   sector_size= ((off_t) buf[8] << 56) | ((off_t) buf[9] << 48) |
+                ((off_t) buf[10] << 40) | ((off_t) buf[11] << 32) |
+                (buf[12] << 24) | (buf[13] << 16) | (buf[14] << 8) | buf[15];
  }
  ret= Sectorbitmap_new(o, sectors, sector_size, 0);
  if(ret <= 0) {
diff --git a/xorriso/xorriso_timestamp.h b/xorriso/xorriso_timestamp.h
index 165d3e08..7acec05a 100644
--- a/xorriso/xorriso_timestamp.h
+++ b/xorriso/xorriso_timestamp.h
@@ -1 +1 @@
-#define Xorriso_timestamP "2024.04.20.145515"
+#define Xorriso_timestamP "2024.04.27.163443"