Qs about Linux setup on Compaq 486 notebook

[Bhaskar Manda <bhaskar@or4.me.uiuc.edu>]

I'm want to use Linux on a Compaq 486/25SL notebook. I'm stuck on
the following issues and would appreciate any pointers.
1 I believe the video ROM is being shadowed. The BIOS setup
 has options to shadow the video ROM at two different addresses,
 but none to turn it off.
2 Some memory is reserved, presumably for shadowing arcane stuff,
 including but not limited to battery management pop-ups (or is that
 in the video RAM?).
3 Who is reserving this memory? Does the BIOS do it? Or is it DOS?
 Since Linux (Debian) install instructions ask you to turn off all
 shadowing, I can do that automatically if DOS is doing the shadowing,
 but I get the impression that the BIOS does this. The how do I go
 about disabling shadowing and not reserving memory?
4 These machines were supposed to have a small partition with
 diagnostics programs on it. I don't see anything but a Big-DOS
 partition with FIPS and other HDD utilities. Can there be a parition
 that such an utility cannot see? 
5 Some utilities I have used show 256k video RAM, but there's supposed
 to be 512k. The same utilities see 16450 UARTs on my serial port and a 
 16550A on the modem board, but MSD sees 8250s on the serial port.
 How reliable is this stuff? Are there definitive h/w utilities in Linux?
6 After resizing partitions using FIPS, the installation boot disk
 vomits a hda: read_intr: 0x40, but I figure that's because of wrong
 information in the BIOS.

I'm looking at the Troubleshooting info in the LDP and the PC h/w faqs.
Any information will be highly appreciated.
Thanks,
-bhaskar