Triumph Adler Walkstation 386SX 25 BIOS Dump (CTHJ03 0214 / CTHJ03 0220)

  • Hello,

    After finding a bit of information about the power supply, i thought it would be nice to share something back.
    My Walkstation is working fine, but the harddrive is at its end (It wont release the parking magnet sometimes).
    Therefore i thought a CF card would be a better solution, but the Cylinder/Head/Sector count is not the same as this CF Card.

    Therefore the first sector can be read properly but won't boot.

    So after playing around with writing BIOS'es a while ago, i thought adding this CF card option to my Walkstation.
    The IDEINFO.EXE perfectly shows whats going wrong: The installed Conner CP2084 got a CHS of 532/8/39.
    The Sandisk CF card needs 980/16/32. Especially the 16 Heads / 32 Sectors is important. The Cylinder is just a multiplication.

    So i took the BIOS FLASH from my motherboard and dumped it contents. It might be valuable for others as well (writing emulators, I cannot find it elsewhere on the internet).

    The label on the BIOS Flash chip says 'CTHJ03 02 14', but whats actually inside is 02.20 release'.

    When i finish the modification, i will upload it once again.

    P.S. If its not allowed to post 28 year old BIOS files (Copyright Olivetti?) please remove the attachment. It is not my intention to violate rights, but just to preserve things from the past.

    Kind regards,

  • Hi,

    No working solution update right now, but analyzing the BIOS dump file i found out that the 128Kb BIOS FLASH contains:

    - VGA BIOS (marked 55AA as option rom)
    - (EXTENDED) BIOS Utility for configuration
    - The actual BIOS defining the interrupts and POST.

    Luckily it turns out that IDA (a great disassembler) has its 7.0 released as freeware for x64. It works also for 16bit real mode.

    Some strings are found that shows hidden options, I also noted some LPT (0x378) and COM port (int 14h) communication during startup.

    For the CF Card modification i will need to alter:
    - The visual setup thing to select the CF Card mode and save it to NV RAM.
    - The actual BIOS/POST setting the right contents where DOS can find the HDD info.