Arch Linux

El roux

Member

Registered: 2010-02-06

Posts: 3

Dual arch boot (i686 + x86_64) kernel related question

Hi everyone,
I had the need to use full 32 bit and 64 bit system, so I installed my main arch as the 64b and I made two dedicated 10gb partitions for the 32b system, one for the "/" and one for the "/home" of the 32b. The rest of my hard drive is divided into the 64b "/", "/home" and "/boot" (plus swap and windows partition). The 64b. version was already installed and the 32b installed fine.

I taught I could use grub to boot both system, so I mounted the 64b system's "/boot"  for the two system as /boot (in fstab). I didn't realize that both of them were using the "vmlinuz" file in the "/boot" as their kernel, so I wasn't able to boot the 32b system. I chrooted and did a pacman -Syu form a liveusb 32b arch iso, but it kind of "crunched" the 64b vmlinuz and initrd....the /boot of the 64b was mounted

So for now, I am locked off my main arch(64b), stuck with a "dummy" 32bit system (which is working great but lack of my apps) and I have no clue on how to solve this issue.

I taught of solutions, but all of them and their downsides :

->I could boot from the 64b. liveiso and restore the 64b vmlinuz and initrd.

->I could edit the grub.conf/menu file to boot different kernels for the different systems (vmlinuz64 for the 64, vmlinuz32 for the 32) but for each kernel update, I would be forced to edit the new kernel names, not mentioning other issues that could rise.

->I could make 2 /boot partition, but then where do I install grub? I taught it has to be installed on only one /boot to look for its config files so thats not working either...

So how do I solve this? I really need that 32b kernel and I don't wand to reinstall everything!
If you got a dual arch system, how is it organized? What do I need to do in order to have that kind of system?
Thanks for the time reading me!

MoonSwan

Member

From: Great White North

Registered: 2008-01-23

Posts: 881

Re: Dual arch boot (i686 + x86_64) kernel related question

You could try a variant of your idea "->I could make 2 /boot partition, but then where do I install grub? I taught it has to be installed on only one /boot to look for its config files so thats not working either..."

On the 32b system load up grub-original (v.199 I think?) and then chroot into the 64b system and install Grub2 to that drive's MBR (or whatever it's called now).  From Grub2 chainload the 32b system and you should have an easy time of things.

El roux

Member

Registered: 2010-02-06

Posts: 3

Re: Dual arch boot (i686 + x86_64) kernel related question

Really some big thanks here!
it worked just fine! At first I taught chainloading was just a windows thing

Now i got my real 64b system with all my apps running again

stqn

Member

Registered: 2010-03-19

Posts: 1,191

Website

Re: Dual arch boot (i686 + x86_64) kernel related question

What I did was symlink /boot/grub to /mnt/boot32/grub/. My /home and /root are symlinked too.

Edit: now that I think about it, I don't think I ever rebooted under my 32 bit system since I installed Arch 64 bit...

Last edited by stqn (2011-08-01 22:27:26)