Multiboot from USB-disk oder -stick

[Detlef]

Hello,
today I spent some time making a somewhat "Multiboot" for my
PandaBoard. Finally it works. :D

Summary: I use a SD-Card for booting. All images and scripts are on
mmc, rootfs are on a USB-disk with multiple partitions (as of now I
have Ubuntu precise server, oneiric server and Arch ARM plus data
partition). With a little manual intervention I can boot all of these
OS without changing the SD-card. I'am just using (standard) u-boot
scripting features.

Question is, should I post the detailed procedure (with setup)
somewhere and is it interesting at all? If Yes, what's the best place
to post it? It's going to be a Wiki article at least.

best regards,
DeJe

PS: I would like if a Omap4 expert could have a look at the "get core
temperature" post here and answer if its working or not on PandaBoard
(w/o ES). ;)

[Tom Mitchell]

Yes please post the info.
I would like to do the same thing with
a USB hard disk so I can have a bit of
extra room to tinker.

--
  T o m   M i t c h e l l

[Giovanni]

I am interested in a tutorial too.

Please, post it somewhere and send us the link.

Best regards,
giovanni

[Pavol Cupka]

i am also interested :)
pavol

[dej...@googlemail.com]

Hello,

I put up a Wiki article at OMAPpedia: http://www.omappedia.com/wiki/Multiboot_using_u-boot
Please feel free to comment, correct or modify if needed.

Best regards,
DeJe

[David Anders]

Deje,

just fyi, the groups are moderated which means some posts need a
moderator to approve prior to the post going to the list.

Dave

[Nicolas Dechesne]

hi,

sorry just seeing this now!

On Sun, Apr 8, 2012 at 3:04 PM, <dej...@googlemail.com> wrote:
> I put up a Wiki article at OMAPpedia:
> http://www.omappedia.com/wiki/Multiboot_using_u-boot
> Please feel free to comment, correct or modify if needed.

many thanks for this contribution.

here are some comments:

- how do you manage the fact that multiple OS might need different bootloaders?
- you seem to imply mostly multiple ubuntu installations, is that
true? or do you intend to support multi non Ubuntu OS ?

what we've been doing so far inside TI to address the same problem is
the following:

[note that in our case it's a multi Ubuntu support only]

- create several partition like you do on USB, and make sure that each
partition has it's own /boot/boot.script with the right root= option
in the bootargs
- once booted into OS1, we use a 'switch' script from a running Panda
that will:
- chroot into the OS2 partition, and make sure the SD card is mounted as well
- run flash-kernel from the chroot, so that it flashes the SD card
with the uImage, initrd, and bootloaders from the OS1 chroot (since
11.10 the booloaders are just packages that can be flashed with
flash-kernel), and generate boot.scr from the content of
/boot/boot.script (from the chroot).
- manually reboot the system, it will boot the new OS

the main advantage here are:
- there is no issue when 'upgrading' or 'dist-upgrading', it just works
- when booting 11.10, you boot with the 11.10 booloarders, and when
booting 12.04, you boot with the 12.04 bootloaders.

the main drawback is that it's a Ubuntu centric solution... but that
might be fine for some people...

if that method is useful, we could post it as well.

[dej...@googlemail.com]

Thank you for your comment.

It's not an Ubuntu centric multiboot. I did not checked Android, but so far all Linux-Distributions on Pandaboard are using u-boot. So you do not need to change the bootloader files (MLO, u-boot.bin). At least, I have an Arch ARM on my USB-Disk booting the same way and being pretty sure Debian ARM will work too. Ubuntu is the only one which updates the boot partition without asking, AFAIK. For Arch, I need to copy a new uImage to the boot partition manually.
But in general you are right. If a system needs different bootloader, it will not work.

Your solution sounds good too. Yes, please post it. May you can modify the article and give this as a second option how to do multiboot.

best regards,
DeJe