Re: [Etherboot-developers] Award BIOS and int 18h problems

[Michael B. <mb...@fe...>]

> > As far as I can tell from reading around, there are no preconditions on
> > calling int 0x18 other than that "data areas such as the interrupt vector
> > table, the BDA, and the Extended BIOS Data Area must remain unchanged
> > [from when the BEV was called]".  Since by BEV is currently pointing
> > straight to an int 0x18 instruction, it's hard to see where I might be
> > violating this requirement.
> Since this code used to work it sounds reasonable, that the BIOS is the
> culprit.
> Is this one of those BIOSes that allow you to specify etherboot in
> the boot order?

Yes; I can specify up to three boot devices, with choices such as
"Floppy", "LAN", "HDD-0", "HDD-1", "CDROM", "SCSI" etc.

Interestingly, I've discovered that Etherboot will not be invoked if LAN
is the second boot device.  If I specify an order of "Floppy", "LAN",
"HDD-0" and boot with no floppy in the drive then Etherboot never starts
up.  Changing the order to "LAN", "Floppy", "HDD-0" brings up Etherboot as
expected.

I'm thinking that I might need to hook straight into int 19, using the
code designed for legacy BIOSes that don't support the BIOS Boot
Specification.  I'm running out of ideas to try.

> > The most annoying aspect of this is that the only to test code changes is
> > to burn them into silicon, and I don't have an EPROM eraser...
> > Any ideas are more than welcome.
> If you have an eepro100 plugin NIC I have an mtd driver that allows it
> to be written/erased in software...

I might have to buy one of those if this goes on much longer.

Michael