Re: booting without filesystem

[Anselm Strauss]

On Apr 19, 2012, at 8:53 AM, Jordan Uggla wrote:

> On Apr 18, 2012 2:30 PM, "Anselm Strauss" <address@hidden> wrote:
>> 
>> 
>> On Apr 18, 2012, at 10:50 PM, Jordan Uggla wrote:
>> 
>>> On Wed, Apr 18, 2012 at 1:23 PM, Anselm Strauss <address@hidden> wrote:
>>>> thanks for the info. so that leaves me with the problem of how to boot a 
>>>> gpt partition where i have written the rescue image to. how do i get the 
>>>> mbr boot code to chainload the gpt boot partition?
>>> 
>>> The grub-mkrescue image is meant to be used as a full disk image, not
>>> dd'd to a partition. Why do you need a GPT label at all? What is your
>>> whole end goal with this?
>> 
>> i like the idea of having all the grub data contained in one image file. in 
>> my scenario i have some hardware where the disk is partitioned with gpt but 
>> holds just one partition with filesystem image files that are mounted 
>> read-only on boot. so for an initial install or update that is done from a 
>> live system booted from usb, i can then just replace the image files and 
>> write the grub image to the boot partition. otherwise i have to install all 
>> the grub files into the live system, copy them to the disk during 
>> installation and hope grub-install succeeds.
> 
> Why not keep everything contained in the grub-mkrescue image, which is
> conveniently already an iso9660 read only filesystem?
> Then rather than dding the grub image to a partition and updating the
> files in the filesystem you do both in one step by dding the new
> grub-mkrescue image to the drive.

the downside of this is that all old images will be removed. also i can not 
update the system from itself, it would overwrite the data where the running 
system is mounted from. i want the partitioning in order to have a certain 
modularity. i guess the only option then is to use grub-install after all.