diff -Nru usb-modeswitch-1.1.9.orig/usb_modeswitch.tcl usb-modeswitch-1.1.9/usb_modeswitch.tcl
--- usb-modeswitch-1.1.9.orig/usb_modeswitch.tcl	2011-08-05 23:40:30.000000000 +0200
+++ usb-modeswitch-1.1.9/usb_modeswitch.tcl	2011-09-28 20:56:40.235554246 +0200
@@ -85,30 +85,35 @@
 # providing these attributes - or not. So more probing
 # is needed
 
-if {[string length [lindex $argList 0]] == 0} {
+set devdir ""
+
+if {![string length [lindex $argList 0]] == 0} {
+	set dev_top [lindex $argList 0]
+	if {[regexp {(.*?):} $dev_top d dev_top]} {
+		set devdir /sys/bus/usb/devices/$dev_top
+	}
+}
+
+if {$devdir eq "" || ![file isdirectory $devdir]} {
+	Log "Top sysfs directory not found using bus id or bus id not given ($devdir); trying with kernel name!"
 	if {[string length [lindex $argList 1]] == 0} {
 		Log "No device number values given from udev! Exiting"
 		SafeExit
 	} else {
-		Log "Bus ID for device not given by udev."
 		Log " Trying to determine it from kernel name ([lindex $argList 1]) ..."
 		if {![regexp {(.*?):} [lindex $argList 1] d dev_top]} {
 			Log "Could not determine top device dir from udev values! Exiting"
 			SafeExit
 		}
+		set devdir /sys/bus/usb/devices/$dev_top
+		if {![file isdirectory $devdir]} {
+			Log "Top sysfs directory not found ($devdir)! Exiting"
+			SafeExit
+		}
 	}
-} else {
-	set dev_top [lindex $argList 0]
-	regexp {(.*?):} $dev_top d dev_top
-}
-
-
-set devdir /sys/bus/usb/devices/$dev_top
-if {![file isdirectory $devdir]} {
-	Log "Top sysfs directory not found ($devdir)! Exiting"
-	SafeExit
 }
 
+Log "Top sysfs directory found ($devdir)"
 
 # Mapping of the short string identifiers (in the config
 # file names) to the long name used here