Hello everyone,
I have a small but annoying problem with a USB boot entry in my grub config. The grub itself is installed on the internal harddisk of the computer and mainly boots into the Ubuntu installed on that disk. But I have another entry in that grub.cfg in order to have the option of to instead boot from a USB drive without having to enter/alter the BIOS. The entry is pretty simple:
> menuentry "Boot from USB drive" {
> insmod part_msdos
> insmod chain
> set root=(hd1)
> chainloader +1
> }
This works on one of my PCs, but not on the other. That machine just writes:
> error hd1: cannot get C/H/S values.
I have googled a bit and found the recommendation load a few more modules:
insmod usbms
insmod uhci
insmod ehci
insmod ohci
Of those, adding "usbms" und "ehci" changes nothing. If I add "uhci" or "ohci", I get a different error message:
> error: disk 'hd0,msdos1' not found.
> error: disk 'hd1' not found.
This sounds to me like he not only still doesn't find the USB drive, but now also can't find its own boot partition (the grub files are on the first partition of the internal harddisk) anymore. :-(
Interestigly enough, I get a similar error if I just open the grub shell and type "ls":
> disk 'hd0,msdos1' not found.
The primary partition on my harddisk is a boot partition in ext2 format. Booting into the Linux installed on the hard drie works without any problem.
Can anybody tell me what it happening here? The same bootloader runs fine on another machine with a different mainboard (i.e. the USB drive boot works), but not on this one.
Can anybody give me any pointers on how to proceed? If you need additional information, just tell me what and I will try to provide it as soon as possible. Any help is appreciated
Best regards, Michael