Re: A strange occurrence

[Felix Zielcke]

Am Dienstag, den 16.06.2009, 14:20 -0400 schrieb David A. Cobb:
> This isn't a development question, but I'm hoping the list's knowledge 
> of GRUB will help me understand it.
> 
> Running Ubuntu 9.04, everything up-to-date, package "grub-pc" version 1.96+
> GRUB-2 was installed after having GRUB 0.9x running for years.  The 
> installation involved letting GRUB chainload GRUB-2 until I saw it was 
> ready for primetime, then running an upgrade script.  I mention that 
> because it's important to know that there is still a GRUB 0.9x image 
> somewhere.
> 
> Trying to get past a nasty problem involving the interaction between a 
> 2003 Phoenix BIOS, and a big 160-GB disk that would not have been 
> available in 2003.  I used BIOS setup to change the disk detection to 
> manual, and made sure the numbers that came up were the same as after a 
> successful boot.
> 
> Booted, and WHOA! I got the system-selection screen from GRUB 0.9x.  
> But, it included versions of the kernel that were not installed until 
> after I switched to GRUB-2.  Actually, the only thing I'm sure was 
> "wrong" was the lack of a colorful splash image.  Well, no, actually, 
> I'm fairly sure the console displays were not the same as the "WELCOME 
> TO GRUB" that shows at the start of the GRUB-2 boot; but it goes past 
> pretty quick, and I could be wrong about that.
> 
> So, maybe I hosed my GRUB-2 installation.  That wouldn't explain how a 
> GRUB 0.9x image was found.  Anyway, I re-installed the package and 
> (re)ran grub-install.  And rebooted.  And got the same screen.
> 
> So, eliminate the one variable I knew was changed: I reset the BIOS 
> Setup to do automatic disk detection.  Voilla!!
> I'm back with the GRUB-2 splash screen, and everything is cool.
> 
> But, I'm puzzled [yeah, that is my normal state].  Did the BIOS actually 
> read a different image?  Or, did the "old" GRUB fail to chainload, even 
> though there is no visible sign during a normal boot that the old GRUB 
> is still around?  If the latter, should I consider writing the GRUB-2 
> image onto the MBR again?  Or, would that be just asking for trouble?

upgrade-from-grub-legacy currently runs grub-install '(hd0)' and which
disk hd0 is, is defined in your /boot/grub/device.map
Robert and me are thinking how we solve that problem at best.
If you tell grub-pc that you want to chainload it from grub-legacy then
it runs the update-grub from grub-legacy to create the menuentry for it
and so updates the kernel list for it too.
Maybe you just had grub-legacy in MBR of 2 (or more) of your disks
installed and then BIOS just loaded not the one you thought it would but
the other one.
I don't see where grub2 would have a problem.
If your BIOS changes the disk order then you have to make sure that on
this disk the right grub is installed to MBR.
-- 
Felix Zielcke