Hello!
I have a Socket 775 - DDR3 motherboard with legacy oprom, it does not support UEFI at all. Right now, i’m using a Gigabyte GTX 750 TI and it works just fine, recently i purchased a Gigabyte GTX 1660, after i plug it in, it let me boot into windows, but as soon as I install the display drivers, the screen goes blank and the system halts.
From what i can gather, this is caused by the GPU not having legacy bios booting support, only UEFI, i’ve tried to make it work with DUET but din’t have any lucky, is there any alternatives, like a “reverse GOP” to re-add legacy oprom to newer UEFI cards?
Thanks
@Aflito - Download GPU-z, and dump vBIOS for me, I assume this cards vbios has legacy vBIOS AND GOP, and the GOP in there is what is causing you issue not lack of vBIOS/legacy area. I will remove GOP for you
To dump vBIOS with GPU-z on the right side, under the brand badge you will see a little arrow in a box, right click that and save vBIOS
Never mind, this is Turing series graphics, you can’t use mod vBIOS due to Nvidia encrypted everything so we can’t play with anything in there
So there is not anything you can do here on the vBIOS side, possibly I can edit motherboard BIOS for you, but I doubt there is anything there helpful relating to this since it’s so old
You will need other newer model card that you can edit vBIOS in (Search about that in google for whatever card series you look at before you purchase), or just get AMD card instead, those we can edit vBIOS without issue 
That, or go back to the 750 Ti
Wow! Thanks for a very detailed answer, yeah, bummer! I think i will use this card on another PC and install a RX570 on this board.
If it’s worth a shot, here is the bios file i’m currently using, but it’s pretty ancient, G41 chipset and all.
https://1drv.ms/u/s!AuPUo5Nr-1V1kawhWyrCbeQRextTtg?e=eP6swY
The 750 TI is going to a new owner soon hahaha
@Aflito - You’re welcome! Sorry we can’t modify that 1660 vBIOS 
RX570 we can modify and remove it’s GOP, if that card gives you same/similar issue, I’ve done this for several users with modern AMD recently so it’s no problem 
I checked your BIOS, yes, this is very old BIOS. I see this model has headless mode, randomly people are looking for this so dropping here in case anyone searching later (can you please post the full model name, and or motherboard model name etc - thanks) I See G4177L0D / LORD G4x
I don’t see anything useful in there in regards to GOP/Legacy option rom loading etc, as expected, this system is just to old for that. So, modern graphics card will need mod vBIOS to remove GOP, if and when it causes boot or post-driver load in windows.
Generally when i see this issue, user cannot even boot to windows, so what you may be seeing is dead/dying graphics card and not an issue with this system. Often when card is dying, as soon as you load drivers it messes up, similar to what you mentioned.
Best you test this card on a more modern system, so you can be sure it’s functional and not dying, especially if you just purchased it used or new etc.
@Lost_N_BIOS Yeah, the card is brand-new, gotta ensure to use that 3 year warranty if defective then
I imagine this board can pop up a lot in places like this. I’ve made a thread here listing all my research on this model.
[Resources] Generic socket 775 chinese motherboards - Xeon Mod Information (771 CPU)
My particular one is : Brand TCN, model G41. I’m using other brand bios tho, but it’s essentially the same board.
Yes, I would test on some other modern system as soon as possible then since it’s supposed to be brand new.
Thanks for the thread/info, I grabbed what info you posted on the other thread too already.