diff --git a/src/isofs_wrap.c b/src/isofs_wrap.c
index e9363c75..cdd50d94 100644
--- a/src/isofs_wrap.c
+++ b/src/isofs_wrap.c
@@ -71,7 +71,8 @@ uint32_t iso_read_lsb(const uint8_t *buf, int bytes)
 
 /* API function. See libisoburn.h
 */
-int isoburn_read_volset(struct burn_drive *d, struct isoburn_read_opts *read_opts, 
+int isoburn_read_volset(struct burn_drive *d,
+                        struct isoburn_read_opts *read_opts, 
                         struct iso_volset **volset)
 {
  int ret;
@@ -79,7 +80,12 @@ int isoburn_read_volset(struct burn_drive *d, struct isoburn_read_opts *read_opt
  enum burn_disc_status status;
  struct isoburn *o;
 
- assert(d && read_opts && volset);
+ if(d==NULL || read_opts==NULL || volset==NULL) {
+
+   /* >>> program error */;
+
+   return(-1);
+ }
 
  ret = isoburn_find_emulator(&o, d, 0);
  if (ret < 0)
@@ -111,6 +117,7 @@ int isoburn_read_volset(struct burn_drive *d, struct isoburn_read_opts *read_opt
      return -1;
 
    o->target_volset = *volset;
+   iso_volset_ref(o->target_volset); /* protects object from premature free */
    return 1;
  }
  
diff --git a/test/xorriso.c b/test/xorriso.c
index 2a07c38a..780ebdef 100644
--- a/test/xorriso.c
+++ b/test/xorriso.c
@@ -3409,7 +3409,7 @@ int Xorriso_option_dev(struct XorrisO *xorriso, char *adr, int flag)
    ret= Xorriso_give_up_drive(xorriso, flag&3);
  else
    ret= Xorriso_aquire_drive(xorriso, adr, flag&3); 
- if(ret<=0)
+ if(ret<0)
    return(ret);
  if(Sfile_str(xorriso->indev, adr, 0)<=0)
    return(-1);
diff --git a/test/xorriso_timestamp.h b/test/xorriso_timestamp.h
index 6dd918dc..f84a485b 100644
--- a/test/xorriso_timestamp.h
+++ b/test/xorriso_timestamp.h
@@ -1 +1 @@
-#define Xorriso_timestamP "2007.10.18.221756"
+#define Xorriso_timestamP "2007.10.18.225654"
diff --git a/test/xorrisoburn.c b/test/xorrisoburn.c
index 21fbfb53..b39c718f 100644
--- a/test/xorrisoburn.c
+++ b/test/xorrisoburn.c
@@ -184,9 +184,9 @@ int Xorriso_aquire_drive(struct XorrisO *xorriso, char *adr, int flag)
  xorriso->in_volset_handle= volset;
  ret= 1;
 ex:
- if(ret<=0) {
+ if(ret<0) {
 
-   /* >>> ??? give up not-so-suitable drive ? */;
+   /* >>> give up drive */;
 
  }
  Xorriso_process_msg_queues(xorriso,0);
@@ -210,7 +210,8 @@ int Xorriso_give_up_drive(struct XorrisO *xorriso, int flag)
                              "on attempt to give drive up", 0);
    isoburn_drive_release(drive,0);
 
-   iso_volset_free((struct iso_volset *) xorriso->in_volset_handle);
+   if(xorriso->in_volset_handle!=NULL)
+     iso_volset_free((struct iso_volset *) xorriso->in_volset_handle);
    xorriso->in_volset_handle= NULL;
    xorriso->volset_change_pending= 0;