Hosed Grub with the push of a button

max maximilianbianco at gmail.com
Thu Apr 17 02:35:12 UTC 2008


max wrote:
> Jim Webb wrote:
>> max wrote:
>>> I hosed grub. I need to fix it. I booted from fedora rescue. I chroot 
>>> to /mnt/sysimage. All good. I tried :
>>>
>>> grub-install  /dev/sda
>>>
>>> The  file /boot/grub/stage1 not read correctly
>>>
>>> tried:
>>>
>>> grub-install /dev/VolGroup00/LogVol00
>>>
>>> The file /boot/grub/stage1 not read correctly
>>>
>>>
>>> tried:
>>>
>>> cd /boot/grub
>>>
>>> cat stage1
>>>
>>> output maybe human readable by some humans but not this one.
>>>
>>> So far I can still see all the user files so I can backup and 
>>> reinstall but that wouldn't teach me anything.
>>> All suggestions/insults/how-to's welcome.
>>>
>>> Max
>>>
>> Max,
>> I looked this up on Red Hat's KBase:
>>
>> http://www.redhat.com/docs/manuals/enterprise/RHEL-5-manual/en-US/RHEL510/Installation_Guide/s2-rescuemode-boot-reinstall-bootloader.html 
>>
>>
>> Hope this helps,
>> Jim
>>
> 
> Thanks for the link but i had tried that and it didn't work. The 
> following explains why but I don't see an easy way to do it, i'll do it 
> the hard way , its the only option left, I need some help on best method 
> or whether its even possible.
> 
> 
> 
>  From rescue cd, l let me outline what i see like a terminal :
> 
> sh-3.2# chroot /mnt/sysimage
> sh-3.2# cd boot
> sh-3.2#ls
> boot    grub (there shouldn't another boot directory should there?Also 
> no config files, no initrd, no system map,no vmlinuz, will 
> copying          from another f8 be good enough to restore these, i 
> would guess yes but I am getting hungry so i'll deal with that first, 
> i          should have noticed these missing yesterday but it was late 
> etc....rest of this probably doesn't matter but for 
> the                     sake  of thoroughness i'll go through everything 
> anyway)
> 
> sh-3.2#cd grub
> sh-3.2#ls
> device.map        ffs_stage1_5        reiserfs_stage1_5    vstafs_stage1_5
> device.map.backup  iso9660_stage1_5    stage1                
> xfs_stage1_5   
> e2fs_stage1_5        jfs_stage1_5        stage2               
> fat_stage1_5        minix_stage1_5        ufs2_stage1_5
> 
> I notice as I type this that menu.lst, menu.lst.backup, and 
> splash.xpm.gz are all missing, i'm not quite sure how to regenerate 
> them, I could copy them from my other box but menu.lst won't be 
> identical.....i'll have to think about that one but without missing 
> files in boot what does it matter?Missing files would explain why grub 
> says it can't find stage1, presumably it needs the missing files in 
> /boot to locate stage1
> 
> If you remember I noticed another boot directory inside /boot
> 
> sh-3.2#cd /
> sh-3.2#cd boot
> sh-3.2#ls
> boot     grub
> sh-3.2#cd boot
> sh-3.2#ls
> grub
> 
> sh-3.2#cd grub
> sh-3.2#ls
> 
> device.map        ffs_stage1_5        reiserfs_stage1_5    vstafs_stage1_5
>                   iso9660_stage1_5    stage1                xfs_stage1_5   
> e2fs_stage1_5        jfs_stage1_5        stage2               
> fat_stage1_5        minix_stage1_5        ufs2_stage1_5
> 
> 
> It is the same as the contents of the other grub directory minus the 
> device.map.backup. I don't think this directory should exist at all but 
> it may have been created by my earlier attempts to fix grub. While I 
> don't think it should be there, i don't think it should cause a problem 
> because I never told grub to look in /boot/boot/grub , without the 
> missing files from /boot i think i'm screwed. Will copying these from 
> another f8 do the trick? I think that is the question of the moment. I 
> am thinking yes because these boxes are updated to the same point(i've 
> complied a kernel or two so i think it will work) but how much trouble 
> will it cause? Well I'm off to dinner. All suggestion, insults, etc
> 
> Thanks
> 
> Max
> 
> 
> 
Well I copied all the files from boot that I needed to the other 
machine. Two files system.map and vmlinuz would not copy because they 
were in use but these are created on the fly for the running system, I 
think, i'd appreciate some confirmation here. The other thing I did was 
to blow away the contents of the /boot/grub. Then i did :

#grub-install /dev/sda

The file /boot/grub/stage1 not read correctly.

I can't imagine that menu.lst or the splash file are that important but 
grub.conf probably is, i would have thought that installing grub would 
create one, so I will recreate that next and see what happens, i'll pull 
a copy of the splash and menu.lst in too and modify what needs modifying 
from memory.

thanks,

Max




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