Re: Switching to another boot device on failure

[Venkata Subbarao]

Once again Thank you Andrei.

Modified the grub source and added grub_exit (). After this BIOS booted from next device.

I am now working on a solution where if the UUID present in the grub.cfg goes bad.

One way I am thinking is to check the CRC of the grub.cfg and other image files required for booting. This may be bit lengthy.

Let me know if you have suggestions.

Thanks,

Subbarao

On Wed, Nov 19, 2014 at 8:57 AM, Venkata Subbarao <address@hidden> wrote:

Thank you very much Andrei.

I will try out this and update.

- Subbarao

On Wed, Nov 19, 2014 at 8:46 AM, Andrei Borzenkov <address@hidden> wrote:

В Tue, 18 Nov 2014 10:51:00 +0000 (UTC)
Venkata Subbarao <address@hidden> пишет:

> Hi All,
>
> I am working on a task on XUbuntu OS in which due to any reason if booting
> fails I would like to switch to another boot device by zeroing the MBR of
> current boot disk. Is this possible ?
>
> For example instead of showing following prompt, I would like to zero out
> the MBR so that the BIOS can select next boot device upon reset.
>
> error: no such partition
> grub rescue>
>

grub supports only very limited and controlled ways to write to
device/file. Doing something like this in unattended manner is probably
way too dangerous.

What would be possible is to optionally exit grub (after timeout) in
this case; then BIOS should proceed to next boot device.