Hi there. I'm trying to boot an old Zenith 386SX PC with
NetBSD-current. Unfortunately the boot loader doesn't work.

It seems that the first int $0x13 in the primary loader works
although the int $0x13 in _biosread hangs the system. All of the
messages are printing correctly so the system is switching modes
fine. Has anyone come across this problem before.

Ideas that I currently have (I have discounted some by now)

1) A20 buggered. I know that things are working correctly by
checking if I can access > 1MB in protected mode. It's fine, but
does the bios make assumptions about how A20 is set? I'm looking at
this one.

2) Some BIOS data area/stack is being messed around when we first go
into protected mode. The result being that when we come back to real
mode things are not quite as we would like them.

Ideas?

Alex.