diff -ur vdr-2.4.4-ORIG/vdr.c vdr-2.4.4/vdr.c
--- vdr-2.4.4-ORIG/vdr.c	2020-05-18 18:47:29.000000000 +0200
+++ vdr-2.4.4/vdr.c	2020-11-17 12:15:16.605470457 +0100
@@ -413,11 +413,14 @@
                     fprintf(stderr, "vdr: invalid instance id: %s\n", optarg);
                     return 2;
           case 'l': {
-                    char *p = strchr(optarg, '.');
+	 	    int len = strlen(optarg);
+		    char copy[4]; 
+		    strncpy (optarg, copy, len);
+                    char *p = strchr(copy, '.');
                     if (p)
                        *p = 0;
-                    if (isnumber(optarg)) {
-                       int l = atoi(optarg);
+                    if (isnumber(copy)) {
+                       int l = atoi(copy);
                        if (0 <= l && l <= 3) {
                           SysLogLevel = l;
                           if (!p)
@@ -432,8 +435,6 @@
                              }
                           }
                        }
-                    if (p)
-                       *p = '.';
                     fprintf(stderr, "vdr: invalid log level: %s\n", optarg);
                     return 2;
                     }