Re: Only 4 out of 32 kB of bootrom recognized

[Holger Austinat <austinat@informatik.uni-stuttgart.de>]

> >The strange thing is that only 4 kB are mapped into the ROM area (at
> >C800:0000, verified with 'romcheck').  The 'i' option of romcheck for
> >this ROM gives the desired information (i.e. netboot 0.9, ...), but
> >the 'n' option says there is no netboot image to be found.
> 
> Do you perhaps have some other extension BIOS at C800:0 too? It's a
> popular address for SCSI BIOSes, etc.

This is definitely not that case.  Our PC just contains the graphics
adapter (a Matrox Millennium G200) and the NIC (D-Link DE-528 CT) --
it has no other devices at all (no hard disk, IDE controller disabled,
and , no other card(s)).


We made some progress ourselves:

- Our failed attempts were with netboot-0.9; the D-Link packet driver
  (downloaded from D-Links website at http://www.dlink.com), however,
  was properly recognized (when booting from floppy).

- The next attempt was to use netboot-0.8.1, and this time the full 32
  kB of the bootrom were recognized; but now we had a different
  problem: the packet driver (the same which worked vor 0.9) was
  considered faulty.

- Finally, we selected the NE2000 packet driver (again with
  netboot-0.8.1) which seems to work (the system is sending BOOTP
  requests, gets its kernel, and starts booting ...)

(The card's chipset is a Realtek 8029.)


Some more info on the first mis-attempt: when reading the bootrom with
the EPROM burner, it shows the proper data:

  55 aa 40 ...

'55 aa' is necessary for a proper rom image, and the 0x40 specifies
that the bootrom size is 0x40 = 64 times 512 bytes, which is 32 kB.
When plugged into the D-Link card, the first three bytes read

  55 aa 08 ...

which says the bootrom is 0x08 = 8 times 512 bytes, i.e. 4 kB in
size.  We have no clue how the NIC, the BIOS or whatsoever can modify
this value!


Are there any explanations?

  Holger Austinat
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