Excerpts from netbsd: 13-Aug-97 NetBSD 1.2.1 bootblock fail.. Bill
Squier@guinness.cs. (2686)

> After installing NetBSD on the primary IDE drive (wd0, PCI controller), the
> bootblock fails to load with a "Read error".  I'm unsure what's producing 
> the message, but I assume it's the bootblock code.

Yes, this is the sector 1 code unable to read the remainder
of the boot code.
If there are no geometry problems, this can be a bug of the BIOS
not telling the right boot device to the bootcode. I observed
that with an older Phoenix BIOS.
You can either hardwire the boot device 0x80 in the boot code
or use a boot selector.

best regards
Matthias