diff -u -r initrd.old/scripts/casper initrd/scripts/casper
--- initrd.old/scripts/casper	2006-10-01 04:32:26.688248250 +0200
+++ initrd/scripts/casper	2006-10-01 04:34:44.844882500 +0200
@@ -245,8 +245,8 @@
 }
 
 is_usb_device() {
-    sysfs_path="${1#/sys}"
-    if /lib/udev/path_id "${sysfs_path}" | grep -q "ID_PATH=(usb|pci-[^-]*-usb)"; then
+    sysfs_path="${1}"
+    if /lib/udev/path_id "${sysfs_path}" | grep -qE "ID_PATH=(usb|pci-[^-]*-usb)"; then
         return 0
     fi
     return 1