Old box, new install, Grub fails error 18

alexc ulist at gs1.ubuntuforums.org
Tue Jun 14 03:44:07 UTC 2005

abo Wrote: 
> For the record, I experienced boot problems with both lilo and grub on a
> Thinkpad T42p, which is not that old. Lilo was giving me "L 99 99
> 99...", and grub was giving me error 18.


> It turns out the Thinkpad bios has an option to protect the special
> 4.5G setup non-partition at the end of the disk (Accessed under
> "Security" options). When set to "normal" this hides the last 4.5G of
> the disk. It seems Linux is not tricked by this, and sees the whole
> disk, so LILO and grub get installed with the whole disk geometry.
> However, when booting, LILO and grub use the BIOS, which reports the
> fake geometry minus the 4.5G, causing both LILO and grub to barf.


> Setting the bios setting to "disabled" makes the bios geometry match
> the real geometry, allowing LILO or grub to boot.


> Note: the "Free" 4.5G at the end of the disk that the debian-installer
> partition tool shows you actually has the IBM Setup stuff. I have seen
> some info that suggests on the T42p this is shown as a fat32 partition,
> but on my system it showed as empty. You can overwrite this stuff, but
> it means the IBM recover features (that basically does a fresh winXP
> install from this partition) will not work. Search the web for info on
> how this Setup data can be burned to 7 CD's so you can restore it later
> if you want to.


> Also, this bios option also has a "secure" option in addition to the
> "normal" and "disabled" option. This claims to both hide and protect
> the non-partition from modification. I suspect that Linux will bypass
> this protection also, but it could cause other problems during
> installation if it really did "protect" that area from writes.



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