Last Part - The Fix for MS-DOS 6.22 DOM boot

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    Another day had passed and I’ve remembered that I have BIOS dumps of other machines like this WYSE. There are many Single Board Computers (SBCs) that use this Geode CPUs and CS5536 companions from where you can get a BIOS dump. I have an extracted DiskROM image for a known system EPX-GX500 that is made to work with DOS 6.

    In the DiskROM image is the Interrupt 13 ISR. So the easiest way to make this WYSE boot DOS 6 was to swap this DiskROM in the BIOS. This will replace the INT 13 ISR with a good working one. I have done just that!

Hurray !!! the WYSE booted into DOS 6.22.

The final patched BIOS for WYSE Sx0 - S50 can be found here.

    Now for someone to make this WYSE work like this, it needs to find a way to burn this BIOS to the SST49LF020A chip, either by using my Arduino programmer, or by the mean of some software.

    For other WYSE terminals that have similar problems the same method can be used. DiskROM must be compatible with all Geode systems.

    Don't use this BIOS for other WYSE models, you might brick your machine.







The final DOM image:

    For my WYSE Sx0 -S50 I have used a DOM of 128 Mb. The original DOM from the machine has 64 Mb and its MBR is custom made in such a way that windows machines will freeze if you try to read the DOM. You can find an image of the original DOM in here if you want to investigate this further (Partition Table is not at the standard offset and most code is 32bit).

    A clean image for 128Mb DOM with MS-DOS 6.22 can be found here. To burn this image to the DOM you will need a working Windows machine, a USB to IDE interface, an IDE to DOM adapter and software to burn the image to the DOM.

DOM to USB
    The "USB3.0 to IDE/SATA" interface can be found on AliExpress. 

    The DOM adapter can be found on AliExpress by the name of "44 pin 2.5 IDE male to male adapter"

    And for the software I have used this tool that I found on https://hddguru.com

    Burn the 128Mb DOS 6 image to the DOM, insert the DOM back in the WYSE machine, connect power to the machine and enjoy the new retro machine !!!



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