update-grub failing only reporting "exiting with value 1" when problems with /boot/grub/device.map

[Arthur Marsh]

Hi, I had an update-grub fail only reporting "exiting with value 1".

I eventually found the problem that /boot/grub/device.map was 
inaccurate, due to having to use different device names as I sometimes 
have usb drives plugged in when booting which can use the /dev/sda name 
like the SCSI disk.

My working /boot/grub/device.map is:

(hd0)   /dev/hda
(hd1)   /dev/disk/by-id/scsi-SIBM_DCAS-34330W_F3T92021

I use the /dev/disk/by-id/* path for the real SCSI disk, and 
/dev/disk/by-label/* path for any usb drives, but others might be using 
/dev/disk/by-uuid/*.

Could someone please fix the update-grub script to better report a 
failure due to problems with /boot/grub/device.map?

Arthur.