Add an FAQ for reinstalling the bootloader?

[hamishmb]

Hi there,

After moving to a larger disk, I had to recreate the partition table to be able to resize the partitions. This changed the ordering, resulting in a grub rescue screen.

After lots of faffing around, reading the arch linux wiki, reading through the void-installer script, I have managed to reinstall grub through chroot and sort out the bootstrap partition, but I now immediately get an "invalid memory access" error when the graphical menu loads.

It's fairly apparent I'm still doing something wrong here but I'm not sure what. I could try and make an ELF grub image from the live disk and then place that in the bootstrap partition, or run grub-install outside chroot, but I don't expect that to work really. Any ideas? I sort of wonder if the latest grub package is just broken.

Hamish

[hamishmb]

Turns out, even when I disable the graphical menu (someone on IRC suggested this to me), I still have the same problem. I will post back here when I've figured out what's wrong/what the fix is.

[hamishmb]

So still no ideas really. I have a (blurryish) picture of the behaviour though, if anyone is interested.

I wish I'd kept a backup of the bootstrap partition, because it is looking like I'll have to reinstall, sadly. One should be able to reinstall grub, though, so this is a bit ridiculous. Is there a custom GRUB image being shipped during installation or something?

The one generated by grub-install aught to work, AFAICT.

[hamishmb]

For reference, the error is:

Invalid memory access at %SRR0: 00100364 %SRR1: 10003030

And it occurs immediately after the GRUB menu is loaded, with the options and timeout at the bottom visible.

It turns out, I can boot if I boot from a VOID PPC Live DVD/USB and key in the commands in the menuoption heading in grub.cfg that corresponds to the default option. The plot thickens.

[hamishmb]

Also, if I copy /boot/grub.img on the Live CD to /System/Library/CoreServices/grub.elf on the bootstrap partition, then I can get a GRUB rescue prompt, from where I can type the commands to successfully boot. I have checked and it is still all using GRUB 2.06, which is the same as my Live DVD/USB, which does work.

EDIT: If I copy my grub.cfg to /boot/grub/grub.cfg on the bootstrap partition, everything pretty much works, with some errors while loading the menu entry.

I assume configfile is absent in this version of GRUB because of memory use limits in OpenFirmware? Having it there would definitely help with this kind of thing.

We definitely need some better documentation here, it should not be this difficult to get GRUB working again after repartitioning a hard disk.

[kencu]

You probably want to talk about GRUB issues on PPC Macs with this guy:

John Paul Adrian Glaubitz

who basically wrote it. You can most easily find him here:

https://lists.debian.org/debian-powerpc/

He's very very skilled, and quite approachable.

[hamishmb]

Thank you, I will definitely get in contact with him :)