> I've been struggling this evening to make the bootselector
> work on a Compaq (ProLinea?) 4/33s which has a diagnostic
> partition on the first 8 cylinders (~4Mb) of its ATA fixed
> disk. I can make it boot the diagnostic partition by hitting
> F2, hitting F1 just displays "3" and hangs, fdisk -B won't
> let me configure any other boot options.  I'd welcome any
> ideas that people might have. I'm thinking of telling NetBSD
> to use the whole disk, but then I may effectively loose my
> CMOS setup option.

Ah those horrid Compaq disks.....  I gave up on an external disk
cabinet on an old compaq proliant server and bunged a disk onto
the internal scsi channel.  We were only doing OS testing and 
needed a multi-cpu system (didn't need all that disk rack space).

In any case:
Error '3' means it failed to find 0xaa55 in the last word of the
sector it read from the disk.  This is the only sanity check it
does on the read sector before executing the code from it.

You might have a BIOS that doesn't like LBA disk reads?
The bootselect code doesn't have the space to do as much LBA/CHS
checking as the the other bootstraps.

If does have an option (settable by fdisk) to use CHS reads instead
of LBA ones.  But I don't recall seeing the code in fdisk to set it.
Set the byte (maybe offset 0x195) that enables the bootselector to 0x03.

    David