I found the last BIOS version, dated 9/28/98, for the Octek Rhino 12+ here:
http://members.driverguide.com/driver/d ... rid=125126
You'll have to jump through a few hoops to download the file but it is there. Just use Login:DRIVERS, Password:ALL
to get access or you can create your own membership account.
The file contains the BIOS file 98046.BIN and the flash utility. I downloaded it myself and looked at it. The BIOS does not support AMD mobile K6+ CPU's even though your motherboard has the correct CPU voltage settings available. That can be fixed.
It doesn't appear to have support for hardrives over 32GB's but that can be fixed also.
Your motherboard looks like a good candidate for a BIOS patch.