diff --git a/xorriso/sfile.h b/xorriso/sfile.h
index 4ca2ea49..5b0f26fe 100644
--- a/xorriso/sfile.h
+++ b/xorriso/sfile.h
@@ -27,6 +27,7 @@
 #define Xorriso_free_meM(pt) { \
   if(pt != NULL) \
     free((char *) pt); \
+  pt= NULL; \
   }
 
 
diff --git a/xorriso/write_run.c b/xorriso/write_run.c
index 99eed8d2..e3bcafd7 100644
--- a/xorriso/write_run.c
+++ b/xorriso/write_run.c
@@ -3616,7 +3616,7 @@ int Xorriso_adjust_relocated_sb(struct XorrisO *xorriso,
  if(ret <= 0)
    goto ex;
  ret= Xorriso_find_sb_checksum(xorriso, buffer, &vd_end, 0);
- if(ret <= 0)
+ if(ret < 0)
    goto ex;
  if(ret > 0) {
    checksum_block= ret - 1;
diff --git a/xorriso/xorriso_timestamp.h b/xorriso/xorriso_timestamp.h
index eea5508c..9b57d962 100644
--- a/xorriso/xorriso_timestamp.h
+++ b/xorriso/xorriso_timestamp.h
@@ -1 +1 @@
-#define Xorriso_timestamP "2024.04.27.165051"
+#define Xorriso_timestamP "2024.04.27.165316"