diff --git a/drivers/isdn/hardware/avm/b1.c b/drivers/isdn/hardware/avm/b1.c
index 4ac378e48902..40ca1e8fa09f 100644
--- a/drivers/isdn/hardware/avm/b1.c
+++ b/drivers/isdn/hardware/avm/b1.c
@@ -423,7 +423,7 @@ void b1_parse_version(avmctrl_info *cinfo)
 	int i, j;
 
 	for (j = 0; j < AVM_MAXVERSION; j++)
-		cinfo->version[j] = "\0\0" + 1;
+		cinfo->version[j] = "";
 	for (i = 0, j = 0;
 	     j < AVM_MAXVERSION && i < cinfo->versionlen;
 	     j++, i += cinfo->versionbuf[i] + 1)