The ROMs can be read on a standard EPROM reader. You need to tell it they're ST Micro M27C322 (32Mbit, 16-bit wide) ROMs and disable device-ID checking. They match the ones Myelin uploaded elsewhere, so I won't bother uploading them again... you can get them from his thread: viewtopic.php?t=19132
I've set it up with a Zip drive and got it to the desktop ... only problem now is, the mouse cursor won't move, even with MouseKeys or KeyRat loaded
Does anyone know how to get the mouse cursor to move?
Now onto my thoughts about the mods...
PS/2 mod
If anyone wants to do the PS/2 mod, the connectors are available from AliExpress: https://www.aliexpress.com/item/32786896527.html
If that doesn't work, search for "PS2 double socket", "PS2 socket keyboard and mouse" or similar.
It doesn't matter (electrically) but the tracks seem to route the bottom socket to the little Philips chip that handles the keyboard and IR remote, and the top socket goes towards the 37C669 Super I/O. My guess is that means the mouse is the top one.
Sadly the bottom PS/2 socket is blocked by the 8-pin socket on the power board. That means either the motherboard will need to be unscrewed and tilted up to access the keyboard port, or the power board tilted out of the way.
In terms of alternative mods - I'm thinking the best option might be to drill holes in the back and fit a pair of chassis-mount mini-DIN sockets.
Annoyingly the pin pitch isn't 2.54mm, but it's close enough that bending the pins on a 2.54mm pin or socket header should be enough to make it fit the PCB. Remove the middle two pins from the left side, and it should be a perfect fit for the PCB.
After that's done, get a PS/2 Y-cable (or a pair of extensions) and cut off the plug end. Crimp a 2x4 0.1in socket onto the ends, wired appropriately.
RISC OS 3.71
Evidently RO3.71 boots fairly well on the stock hardware, as a 4MB ROM.
I figure we probably want to cherry-pick some of the changes from Spinner (first-gen NC) and Kernel 5.13 branch of the RISC OS Open codebase: https://gitlab.riscosopen.org/RiscOS/So ... ernel-5_13
Chances are we'll want --
* Up to 16MB of ROM mappable - https://gitlab.riscosopen.org/RiscOS/So ... 8111a85eb1
* First attempt to get POST working on 8MB ROM - https://gitlab.riscosopen.org/RiscOS/So ... 608b60aea0
* More adjustments to 8MB ROM situation - https://gitlab.riscosopen.org/RiscOS/So ... d16fbc7dd3
There are some other changes related to the 669 Super I/O and blinking the front panel LEDs if the POST fails, they'll probably be needed later on, but just the 8MB ROM changes and some build system tweaks should be enough to get an 8MB kernel image.
Going further might require an ArcFlash for the Bush, but who knows... the PCMCIA slot next to the ROM socket is apparently for a flash ROM cartridge (likely PCMCIA linear Flash or some custom thing).
Interestingly the NC remote allowed delete-power-on using the right arrow key: https://gitlab.riscosopen.org/RiscOS/So ... 56a0b352df
It's up for debate whether this protocol is what the Bush NC keyboard uses, via the little Philips IR/PS2 chip.
Relevant codenames in the ROOL source --
- Spinner - first-gen NC
- Lazarus - Internet TV
- Bethany - multilingual Internet TV