install 4.9 on a Gericom laptop

[Sebastian Posch]

Hello!

I'm trying to install FreeBSD 4.9 on an old laptop. it is a Gericom 
Pentium 100Mhz, 24MB RAM, 560MB hard disk, unable to boot from CD. btw 
I'd update the BIOS but it looks like i won't find an update to this old 
system ("SystemSoft SCU BIOS").

there was Windows95 installed, HD/CD-ROM etc. worked fine.

after booting with floppy and setting mount points and running the 
sysinstall and all that, I get a "unable to swap to dev/ad0s1b" and then 
"unable to mount root filesystem".

before rebooting I try Alt+F2 and I get the following:

ad0: hard error writing fsbn 74 (ad0 bn 74; cn 0 tn 1 sn 11) status 51 
error=04
ad0: cannot find label (no disk label)
ad0s1: cannot find label (no disk label)
DEBUG: Scanning disk ad0 for root filesystem
DEBUG: Found rootdev at ad0s1a!
DEBUG: Found vardev at ad0s1e!
DEBUG: Found tmpdev at ad0s1f!
DEBUG: Found usrdev at ad0s1g!
DEBUG: Scanning disk ad0 for swap partitions
DEBUG: Found swapdev at ad0s1b!
ad0: cannot find label (no disk label)
ad0s1: cannot find label (no disk label)
...
newfs: /dev/ad0s1a: Invalid argument
DEBUG: Command 'newfs -b 16384 -f 2048 /dev/ad0s1a' returns status of 1

-

I tried different params to newfs (such as half or double the value) to 
no avail. I also tried several different partitioning than the automatic 
settings.
Google told me to try booting with "hw.pcic.intr_path=1, hw.pcic.irq=0, 
hw.ata.atapi_dma=0" but that didn't change a thing either. I even tried 
to install Debian 3.0 but it seems it also doesn't like that hard disk.

Does anybody have a recommendation?