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Re: How to use a particular kernel for only one boot




Roberto C. Sánchez <roberto@xxxxxxxxxx> writes:

>On Tue, Mar 06, 2018 at 07:35:37PM +0000, John wrote:
>> I am still looking for a clean way to upgrade my Debian box.
>> 
>> Background is that the m/c is the interface to the world from the LAN,
>> runs headless, and is fairly difficult to access physically.  My
>> attempt to upgrade from Whezzy to Jessie broke as it would not
>> run/load the 3.16.0-4-amd64 kernel, and after a painful period I
>> managed to get Jessie running with the Whezzy 3.2.0-4-amd64 kernel.  I
>> have uploaded the 3.16.0-5-amd64.  What I would like would be to try a
>> boot into the new kernel, but if that fails for the next and
>> subsequent boots to be to the (working) Whezzy kernel.  I think I
>> heard once that there was such a mechanism but  have not found it.
>> BTW it is running grub.
>> 
>grub-reboot (8)      - set the default boot entry for GRUB, for the next
>boot only
>
>Regards,
>
>-Roberto
A caveat - if your boot directory is in a raid parition grub will not
reset the boot environment - it knows how to read but not write raid
partitions.

If you boot successfully you can reset it yourself - but if the boot fails
you will be stuck.