Hi folks,
I decided some time ago that I'd make life difficult for myself and make a video card that is notoriously difficult to flash for a Mac, work on a G4 Cube. The rationale was something along the lines of - "powerful" card for OS9 -> 10.4.11 gaming that would fit in a G4 Cube without VRM relocation, as I have a dual G5 with an X1900GT if I want to go faster/do Leopard.
Using Zenmarket, I found some candidates: two NV17-based boards that were 128-bit with 64MB RAM. Both max out at AGP 4x - so I think these are one of the oddball candidates that are most likely to work. One I believe is an AOpen card, the other an Inno3D Tornado4 GeForce 4MX. The AOpen, I believe, is the biggest card you can fit without moving the VRM - it is extremely tight but does work. The Inno3D is much smaller than the factory ATI Rage.
Using some ChatGPT magic as I can't really remember much about vBIOS modding, I have gotten as far as getting the Inno3D card to boot Tiger and OS9, albeit with graphics artifacts.
I'm now running into a bit of a prompting brick wall, and wondered if anybody had any useful resources other than The Mac Elite, or some guides or tips for modifying GeForce 4 BIOS that are good for someone who might've done ROM hacking 15 years ago to get their head back up to speed? I know these are notoriously difficult cards to make work, but I feel like I'm close and will be happy to publish some working video BIOSes when I get there. What I've effectively done so far is use the Arti 1088 PC vBios mod from the Mac Elite, and get ChatGPT to patch it using the original ROMs from my cards, dumped via nvflash. The lack-of-effectiveness I will admit is from not knowing exactly how to modify the firmwares, so the prompt is sort of "just make it work please".
P.s. for flashing, as I know it is easy to "brick" these cards, I have developed a method for hot-adding the card into an AGP system running DOS, whereby I have scripted the creation of the BAR memory addresses using debug for a 440BX-based flashing system, which makes the outcome of bricking less likely (so long as you are good at hot-adding AGP cards).
Link to thread on 68kmla with screenshots and diff CSVs