Flashing the Lindbergh 7800gs to work under OSX-PPC

[SASDakota]

So from all of my internet digging and talking to others who flashed their 7800gs. This card seems to be an oddball that does not work with the existing wikiDL ROMs. My goal is to find out why that is and hopefully share the answer once it works. This thread will serve to be the collection of ideas, successes and failures along the way. Well. Here goes nothin'. Any useful information or major steps taken I will keep updating the first post.

Example card that works (BFG-256mb):
BIOS - 5.70.02.33.07
BIOS Size - 64kb
Die - G70
Card - P492n0

Lindbergh 7800gs (256mb):
BIOS - 5.70.02.46.01
BIOS Size - 62kb
Die - G70
Card - P492n30

Wikidownloads2 GeForce 7800 GS generic (nvflash, gotoh), tmeperature sensor removed for G4 running Leo (gotoh):
BIOS - 5.70.02.16.00
BIOS Size - 64kb
Die - G70
Card - P492n0

 

[SASDakota]

My first question to anyone who may know about these cards. What does the P492n-- number represent?

Current project is to compare a BFG ROM from TechPowerUp to my read out Lindbergh ROM to understand what they do different.

Using Nibitor 6.06 I am able to compare both ROMs as shown here (Mac rom to Lind). I am not going to show all of the screenshots because it would consume a ton of screen space in the thread. This is only to show what I am working on.

 

[SASDakota]

So far, with all the Lindbergh timings swapped into the mac ROM using Nibit and the softstraps using HxD, I get no display out of the G4MDD the mac ROM by itself gave display but with massive artifacting. A result, even a negative one, is a result. I will spend some time thinking and reviewing the changes to determine the next step. Open to suggestions, I can also share my files if anyone wants to review the data themselves.

 

[SASDakota]

Returned GPU to factory BIOS, Booting up the flash PC I'm using into windows XP, installed the latest nvidia drivers for XP Geforce7. I was able to use the Lindbergh as a PC GPU with full 1080p 60hz. Nibitor 6.06 read the card BIOS and autodetect says card is running on timing set 5.

I've compared the file saved from NVflash to the file saved from Nibitor in HxD. They show identical.

Does anyone know what timing set is used on the BFG card/G4 modified ROM?

I could probably load a BFG ROM from TechPowerUp on my Lindbergh here and see what happens...

 

[SASDakota]

BFG ROM from TechPowerUp gives artifacting on the Lindbergh in a PC as the MAC ROM does in the G4MDD.

What is it about the ROM that converts PC to MAC?

 

[SASDakota]

I can now boot OS9.2.2 with the Lindbergh 7800gs.

OSX Sorbet Leopard status: Clear apple screen and loading circle. Crashes or hangs before the desktop.

 

[SASDakota]

Taking a break for the weekend.. I have tried a bunch of tweaks that I thought were going the right direction only to still get hangs on bootup with artifacts never seeing the desktop under OSX. 9.2.2 is looking very clean and seems stable. Artifacts when shutdown however.

Going to ponder this a bit more and try to keep reading the old forums. If anyone has suggestions or wants to see the files I am working with feel free to reach out. I'll share my work once I have a completed product.

 

[SASDakota]

I gave up on the Lindbergh, they use memory chips that I can only assume will not take the timings of the created Mac ROM.

In the process of trying to learn what I could about older NV tuning, Tracked a couple people down that tried in the past before I got to it and they ultimately stopped as well. The closest I came to a working card, was getting 2D graphics (9.2.2 booted and stable) even OSX apple logo. But the second OSX loaded drivers, artifacts came and stability (crashes or hangs) were common. I made it to a VERY buggy dashboard one time, not repeatable. OR I got no display at all. I tried lowering the core and mem clocks. I tried probably 30 iterations of memory timings created with Nibitor. Had extra cooling on the system. None of my attempts seemed to track, I would make improvements then the next iteration would not boot. etc....

In PC mode, the Lindbergh 7800gs ran great under XP Pro with a P4 cpu and Geforce drivers installed. Nibitor under XP said the card was running timingset 5.

In Mac mode, nibitor does not offer voltage adjustments, this may play a factor in all of this for stability. However the XP machine running nibitor did not show any outrageous voltages with Lindbergh ROM loaded so I didn't push the issue.

Ultimately, finding information about this older tech became harder and harder the deeper I needed to go down the rabbit hole. Diminishing returns for my time is what killed it for me. If anyone wants to pick up this project I can provide the ROM that got me the furthest. But I no longer own the card I was testing on. Purchased an EVGA 7800gs and it worked out of the box once flashed.

 

[DearthnVader]

Sorry, I've been away for awhile, we likely could have gotten that card working, but at this point who is really still using PPC.

Sometimes these things are a fun exercise in just making things work tho.