270x Downgrade bios to 7870 for M91p motherboard.

[Shambles1980]

Ok.

here we go after my last bit of tom foolery with SFF prebuilt systems, i bought second one This time its a lenovo M91p SFF..
Standard atx layout, no silly proprietary nonsense (the usff version is to be avoided).. AND YET!
Some one decided to throw in a GPU white list in to the bios.
Why they did this i have no idea.. any way few days on the inter web at places that specifically modify bises, im here still with the same white list. and il admit i dont have enough experience to modify the whitelist out, its hiddn in some module some where and i cant figure it out..

ANY WAY.

it seems that a 7750 AMD card works.
Which should mean all hd 7xxx cards should work..

Now i want to either edit the bios info for a 270x (not on the white list) so its device id is a 7870.
OR
i want to flash the bios of the 270x with a 7870 bios..

Should work fine right??

Any way i have a spare system sitting here that i can boot the 270x in to do the flashing and stuff.
I was just wondering which bios would work out the best??

I know some people will have flashed from a 7870 UP to a 270x so if i knew what bios they had previously that may help..

its an ice-q 270x btw if that makes a difference..

Oh and if some one has a modded m91p bios or can tell me how the hell i find the whitelist to add the 270x'x device id to it, that would also be great.

 

[MrGenius]

I can edit your 270X BIOS to have any device ID you want it to have. I just need to have a copy of your BIOS and the device ID you want it to have. So if you can make a copy it with GPU-Z and upload it as an attachment that would be perfect(throw it in a zip folder first). It looks to me like your 270X is 1002-6810, and an HD 7870 is 1002-6818. It will take me less than a minute to edit that change into your BIOS and fix the checksum. If it doesn't work the we can try an HD 7750 device ID(1002 - 683F).

 

[Shambles1980]

im just trying to find any one who has a "reported working" system with the cards. I dont want to edit the vendor id. and it stil not be in the white list lol..
(if i could find the stupid whitelist in the pc bios i could just edit that)
Even a copy of the whitelist on the internet would be nice.. (you would imagine they would publish that info, but they dont)

So far, i can only see a 260x as being actually in the whitelist. and i was Just downloading a 260x bios to try and grab the vendor id from that..
thats when i saw the reply..

I will search and see if any 7850's are reported to be working.

Its really Stupid to put a GPU white list in a system..
given nvidia cards including 10xx cards are suported it seems a lot like they did this to try and force nvidia cards as an upgrade path.

OK,,
So. i have found 1 person who says the 7850 worked after a bios update. (already updated that thing ages ago) So surely a 7870 should work..

Il upload the rom file here.
Pretty sure i can edit the devce and vendor id my self. but i will also upload it here in case it turns out that im a massive idiot.

ok so i may be an idiot.
I can only change the vendor and subsystem id.

if you could whip up a 7870 and a 7850 ID that would be great.

 

[eidairaman1]

Ok what is the issue? Are you having an issue of a 270 not booting up in a specific motherboard?

 

[MrGenius]

Man...I'm having a really hard time trying to get the SOB to come out the way I want it. I change the device ID in the 2 spots it needs changed, save it, fix the checksum with the HD 7xxx patch tool. Should be good to go. Nope! I open it with VBE7 and it says the checksum is invalid. What?! Alright...then I'll save it with VBE7 so it will fix the checksum. Bah!!! Now VBE7 say the checksum is good...BUT...the UEFI is deactivated.

Long story short...I keep going around in circles trying to get the checksum fixed with UEFI still activated. And I can't seem to figure out how. I've NEVER had this problem before...so I'm not sure how to make it work. There's got to be a way. I know how to manually change the device ID. I know how to manually activate the UEFI. I DON'T know how to fix the checksum without an editor/tool. Shouldn't be that damn hard. I've read about it somewhere...but I can't find where ATM. Godammit...this is making me look bad. Here I said I could do this in less than a minute...AND I CAN'T.

Anyhow...you probably don't need UEFI anyway. But even if you don't I still need to know how to make it so. Really pissing me off.

Here's what I got so far.

1 with UEFI and an invalid checksum according to VBE7(though a valid checksum according to HD 7xxx UEFI patch tool)

1 without UEFI and a valid checksum according to VBE7(though an invalid checksum according to HD 7xxx UEFI patch tool)

I'm not giving up just yet. I know there's a way....somehow. But this is the best I can do for now.

Nailed it! See post below.

 

[eidairaman1]

Man...I'm having a really hard time trying to get the SOB to come out the way I want it. I change the device ID in the 2 spots it needs changed, save it, fix the checksum with the HD 7xxx patch tool. Should be good to go. Nope! I open it with VBE7 and it says the checksum is invalid. What?! Alright...then I'll save it with VBE7 so it will fix the checksum. Bah!!! Now VBE7 say the checksum is good...BUT...the UEFI is deactivated.

Long story short...I going around in circles trying to get the checksum fixed with UEFI still activated. And I can seem to figure out how. I've NEVER had this problem before...so I'm not sure how to make it work. There's got to be a way. I know how to manually change the device ID. I know how to manually activate the UEFI. I DON'T know how to fix the checksum without an editor/tool. Shouldn't be that damn hard. I've read about it somewhere...but I can't find where ATM. Godammit...this is making me look bad. Here I said I could do this in less than a minute...AND I CAN'T.

Anyhow...you probably don't need UEFI anyway. But even if you don't I still need to know how to make it so. Really pissing me off.

Here's what I got so far.

1 with UEFI and an invalid checksum according to VBE7(though a valid checksum according to HD 7xxx UEFI patch tool)

1 without UEFI and a valid checksum according to VBE7(though an invalid checksum according to HD 7xxx UEFI patch tool)

I'm not giving up just yet. I know there's a way....somehow. But this is the best I can do for now.

I suspect he has an old motherboard that needs its bios updated, and could need just the csm, as uefi may not be compatible.

 

[MrGenius]

I GOT IT!!! WHOOHOO!!!

UPDATE: I threw in a UEFI deactivated version just because I can(270xUEFI.rom is the one with UEFI activated, 270x.rom has UEFI deactivated). Let me know if you have any problems.

What the hell...brief tutorial.

How to change Device ID

Open BIOS rom with hex editor and search/find "PCIR" text string


You need to find all instances of PCIR(only 2)


The first 4 hex values after PCIR are the Device ID. For your original BIOS they are 02 10 10 68 = 1002-6810

You need to edit both instances to whatever you want the new Device ID to be. For yours you want 02 10 18 68 = 1002-6818(Device ID for an HD 7870)

Here


And here


Then you need to fix the CRC here


Use Anoraks AMD VBIOS CRC checker v1 to find a new CRC and change it in the BIOS. For yours you need to change 96 to 8E


Save the BIOS and your done.

New Device ID acquired

If you want to make a copy with UEFI deactivated change the hex value below from 00 to 80(vice versa to active UEFI)


Fix the CRC again and save the BIOS.

EDIT: Seeing as the UEFI didn't work after the edit I believe I've figured out how to fix that so it does. I think it's a matter of fixing the actual checksum. Which is not the CRC, though some tools see it as such. See my post below for how to fix the actual checksum...or something. I don't totally get it.

 

[Shambles1980]

il test it when i get back in thanx..

As for the issue..
its a m91p motherboard the bios has a white list in it.
it is on the most recent bios.

its a thing they did "to reduce issues in buisnes"
Although Nvidia cards seem to work fine for 90% of them

edit

ok back home now and did a flash or 2..
Strange issue though..

the flash says it changed the ID.
VBE7 reports it changed the id.
Windows devie manager still sees it as a 200 seriese.
and GPu-Z sees the origional device id..

Heres a picture..
I dumped the bios after flashing to make suer it was properly flashed and that is whats in VBE7
But notice the gpuz ID...
Also UEFI doesnt work (that is not an issue though.

I may just try flashing it with a 7870 bios if i find one that has similar clock speeds and the same type of ram.

 

[Shambles1980]

Ok. scratch that..
Decided to just try it on the m91p as it is.. AND.. It boots no prob..
So The device ID is in the white list (on the most up to date bios at any rate). and the bios sees the same Device ID as VBE7 does.

Really don't understand this add a white list nonsense to the bios to stop people using 90% of amd cards thing. I can only see it as a anti trust thing.
on the lenovo forums you get people saying "amd cards are notorious for not working" when the truth is. "we didn't add most AMD cards to the white list that shouldn't even be there"

Much easier then trying to add the device id to the bios white list. "i couldn't even find the module that had the white list in. let alone edit it lol" (and its easier to recover if you f-up)

SOO it works and boots, its also detected as a 200 series card in windows.

Saved me a lot of work thanks again.

 

[MrGenius]

Also UEFI doesnt work (that is not an issue though.

I'm perturbed by that. So I'm going to see if I can fix it. I think I know why and therefore how. The real checksum needs fixed.

WARNING: Information provided below is based on guesswork. I don't really know what I'm doing at this point. If you know what to do please tell me.

How to fix the real checksum

Find the 8-Bit checksum before editing the BIOS


The 8-Bit checksum is hex 96 = 150


Make all the changes you want to make in the BIOS, save it, and find the new 8-bit checksum. It's now hex A6 = 166


Because the new 8-Bit checksum is larger than before things have shifted in the BIOS. To shift things back to where they were you need to edit the unused bytes at the end to make up for it. These are the long list of FFs at the bottom. I'm not going to claim I know 100% how this works. But I think I maybe figured it out enough to make it work in this case(I hope). It's a different procedure if the new checksum is smaller than previously. And I haven't figured out how to fix that yet. What I've learned so far I got from the following source.

http://www.xtremesystems.org/forums/showthread.php?180607-Tutorial-How-to-fix-a-bios-checksum

Ok...so 166 - 150 = 16. So to fix the checksum you need to subtract 16 from one of the hex FF at the end of the BIOS. FF = 255, 255 - 16 = 239, 239 = hex EF

So change one of the FF at the end to EF


Now save it, find the new 8-Bit checksum, make sure it's the same as it was before editing(notice in pic above that it is), if it's the same as before then fix the CRC, save one more time and you're done.

Attached below is the BIOS where I used this method to try and fix the UEFI. Hopefully it works.

 

[Shambles1980]

Im not at home right now. and with having an autistic daughter as well as a baby i dont think il be able to dedicate the time for flashing and testing again untill saturday evening when the eldest will be at my parents.

But as i said it did exactly what i needed it to do..
tricked the stupid white list in to letting the GPU boot up which is all i wanted it to do, it also has the unexpected benifit of being detected as the correct card in windows..

P.S

Hope you dont get inundated with ID change requests now lol..

Like my other tinker with a prebuilt. i noticed these things are decent spec ex buisines machines that are popping up on the market at around £70..
Which isnt that bad for a i5 2400 + some ddr3 ram + hard disk So i wouldn't be surprised to see others buying them and then thinking their gpu is dead, until they google search and find this thread and figure it out.

Any way. Just like the last one i would again reccomend any 1 who gets one to pair it up with a gtx 750 low profile gpu or a 750ti (one with no pci-e power connector).
Should be a good little system for steaming and low/medium settings 1080p gaming.

the 270x is about the same as a gtx 760 thats why im using it as the card on these things as i find them popping up..

 

[MrGenius]

That's cool. I'm glad it works well enough as is. It's no big deal if you don't want to mess with it anymore either. If you do, maybe let me know if the UEFI fix works, or maybe don't. Up to you. I've got what I wanted out of the deal already. Which was just to teach myself more about this whole BIOS hex editing thing. And that I have. So you don't owe me nothin'.

EDIT: I'm working on a couple different versions of the UEFI fix. So if that version doesn't work you can try one of these. I'll be done messing with them soon. So check back later and I'll have them attached here. Again...no big deal if you want to experiment more or not. I'm learning new things either way.

 

[Shambles1980]

Happy to check them out for you when i have some time (wife just hinted its our anniversary Sunday) so il probably be able to have a go at them saturday.
if i have more free time before then il give it a go..

i can an have flashed gpus with a bad bios then re flashed them with a good one in the past so not worried about that

 

[MrGenius]

I've come to a conclusion on the matter. I fundamentally don't understand the problem or how to fix it. There seems to be more to it than I can find good info on. What I do know is any time I edit a BIOS with UEFI it ends up not working right afterwards. Just the UEFI part(usually). I've never seen the check in the UEFI box in GPU-Z not show up before. That's a new one. What's been happening to me with my card is a black screen during POST and boot until just before the desktop. Which isn't how a non-edited UEFI BIOS works on my system. And nothing I've tried fixes it. And I've tried A LOT of things at this point. Whatever...I don't need UEFI either. It would be nice to have it working. But it's not a deal breaker if it don't.

Anyway. I'm pretty sure I'm nowhere near having figured this one out. But here's a couple more tries...that aren't likely to work any better than the ones before. I highly doubt they'll brick your card. But I also highly doubt they'll fix the UEFI problem. If they do I'll be shocked. I just tried the same tricks with my BIOS and got nothing. Same story as before. At least I know a few more ways that DON'T work now. That's a plus...I guess.

 

[Shambles1980]

just wondering if its anything to do with it needing to be signed..

on the system i flashed with the other day. (does not have a uefi bios "its a core 2 duo") it would be a black screen untill windows loaded.(i use the c2d for most flashing things as it has more connectivity and (pata as well as sata, com ports etc) and the bios is a much more forgiving bios

On the m91p it shows post and works just fine.

im not fussed about not having uefie on it as i dont use secure boot.

 

[Deleted member 163934]

I've come to a conclusion on the matter. I fundamentally don't understand the problem or how to fix it. There seems to be more to it than I can find good info on. What I do know is any time I edit a BIOS with UEFI it ends up not working right afterwards. Just the UEFI part(usually). I've never seen the check in the UEFI box in GPU-Z not show up before. That's a new one. What's been happening to me with my card is a black screen during POST and boot until just before the desktop. Which isn't how a non-edited UEFI BIOS works on my system. And nothing I've tried fixes it. And I've tried A LOT of things at this point. Whatever...I don't need UEFI either. It would be nice to have it working. But it's not a deal breaker if it don't.

Anyway. I'm pretty sure I'm nowhere near having figured this one out. But here's a couple more tries...that aren't likely to work any better than the ones before. I highly doubt they'll brick your card. But I also highly doubt they'll fix the UEFI problem. If they do I'll be shocked. I just tried the same tricks with my BIOS and got nothing. Same story as before. At least I know a few more ways that DON'T work now. That's a plus...I guess.

Did you tried changing something else? For example don't change the ID of the gpu but change the gpu clock and make it with 1 less Mhz compared to default. Does it act in the same way on UEFI or not (black screen during POST and boot)?

If it works fine when changing the gpuclock on UEFI (u see normal post and boot) then maybe changing the gpu ID makes the UEFI section freak out (i read on another topic (forgot what forum) that there are some sort of gpu ids and they sometime remove some ids; the idea is that the new gpu id doesn't really match what UEFI knows and u get no image as result during post, boot, while in windows u get due to drivers that well probably don't need that UEFI section).

L.E.: You can check this topic for UEFI stuff: http://www.win-raid.com/t892f16-AMD-and-Nvidia-GOP-update-No-requests-DIY.html

L.E. 2: The second id you changed is in the gop section (uefi bios section). That section might have a checksum also or it just has no clue what to do with the new id.

 

[MrGenius]

just wondering if its anything to do with it needing to be signed..

Yeah...it's signed. That much I know for sure. The UEFI GOP part anyway. I don't know if that's what's causing the problem or not. Or if there's some kind of checksum for it. Or who the hell knows. All I know is if you mess with the UEFI GOP part of the BIOS it tends to break it. Specifically if the device ID doesn't match up with the original device ID of the card. I guess it gets checked against wherever GPU-Z gets it from. If it doesn't match up with that it's not going to work. Which I learned the hard way.

On that note, I made my FINAL attempt at fixing yours. From messing around with mine all day again I figured out what I could and couldn't do and still have UEFI work. There ended up being 2 ways I could change the device ID without breaking the UEFI. Both involved not touching the UEFI GOP section at all. Just change the device ID in the legacy part and either fix the checksum or fix the CRC. For whatever reason either way works. At least with my card. I can't test if just changing 1 instance of the device ID will work for you. It either will or it won't. If it does then either method should work just as well as the other. But just in case one way doesn't work I made 2 copies. One for each method. Checksum fixed and CRC fixed. If neither works...I'm flat out of ideas. Anyway...they're attached below if you want to try them out(be sure to check the README first).

L.E.: You can check this topic for UEFI stuff: http://www.win-raid.com/t892f16-AMD-and-Nvidia-GOP-update-No-requests-DIY.html

L.E. 2: The second id you changed is in the gop section (uefi bios section). That section might have a checksum also or it just has no clue what to do with the new id.

I had already found that site and used the GOP update tool on my BIOS. It didn't work for me. But I finally got mine to work today by manually installing. Which I still don't know how or why it worked. But for whatever reason it did.

I also tried with the 270X BIOS and it gave me a warning that I didn't like the sound of. But having fixed mine by manually installing the latest UEFI version I decided to take a look at doing that with it. It's got a way funky looking GOP section. So I decided it probably wasn't a good idea to try and mess with. If it was my card and I could sit and fool around with it for hours on end trying to make it work I probably would...but it isn't.

Anyhow...here's what that looked like.

Yeah...I know about the second ID in the GOP section...and why you shouldn't change it. If you do...UEFI won't work. I don't know if it's got a checksum or not. I've read that it doesn't. But there's some sort of checking going on. That much I'm 99.99999% sure of.

 

[Deleted member 163934]

Yeah...it's signed. That much I know for sure. The UEFI GOP part anyway. I don't know if that's what's causing the problem or not. Or if there's some kind of checksum for it. Or who the hell knows. All I know is if you mess with the UEFI GOP part of the BIOS it tends to break it. Specifically if the device ID doesn't match up with the original device ID of the card. I guess it gets checked against wherever GPU-Z gets it from. If it doesn't match up with that it's not going to work. Which I learned the hard way.

from https://www.techpowerup.com/forums/...-7000-series-cards.189089/page-2#post-2965073

2. The problem with UEFI images is that they're compressed, thats why i cant modify them.

http://www.win-raid.com/t892f16-AMD-and-Nvidia-GOP-update-No-requests-DIY.html

The AMD GPU firmware is formed from a Legacy ROM + an optional GOP in a compressed EFI ROM + possibly a microcode, although extremely rare. Only the Legacy ROM is checksummed,

Compressed GOP gets corrupted when you edit stuff in it. Either u find a donor for it and fully replace it, or well uncompress it, edit stuff, compress it back and replace the old one...
Never really worked with GOP stuff, I tried to add to my old Hd 5670 a GOP section but I fail because I constatly get a too big bios file, it has a really big microcode in the bios...

 

[MrGenius]

All the answers your going to get our found in that thread on win-raid. It has nothing to do with compression. That much I fully understand. It has to do with signatures and hashes. The finer details of which I can't quite get a good grip on. I only know what I know. Which is that lordkag fixed it so that it works. By that I mean he managed to patch the GOP module so that UEFI GOP boot will work with an edited legacy BIOS. As in if the edits have been made to a "protected" part of the legacy BIOS, which may or may not be the case. I've proved that by editing just the Device ID(which is apparently not "protected") in the legacy BIOS and still have it(UEFI GOP boot) work.

Now, as to how I got it working on my card(which obviously had "protected" parts of the legacy BIOS edited). I didn't understand what I'd done initially. But after carefully reading and rereading that entire thread I finally figured it out. What I did was install a patched version of GOP 1.63 provide by hellm(using lordkag's patch/modifications) on the last page there. Which was a stroke of luck. Since there were 2 to choose from in his post(patched and unpatched, and neither labeled as to which is which) and I luckily chose the right one on the first try. Otherwise it would still not be working and I would have probably given up on trying to make it work. But since it did work, when all other efforts had failed, I was extremely curious as to why. So I read and read some more until I came to as good an understanding of it as I can.

There's still some unanswered questions. See my post on the last page of that thread. How is it working without using a patched driver? How is it working with Secure Boot ON? From what I understand the basic gist of lordkag's patching of the GOP module consists of modifying it to skip the checking of a hash(which he refers to at one point as a signature) in the legacy part of the BIOS. Not the CRC or the 8-Bit checksum, but an additional hash that gets checked before UEFI GOP can be initiated at boot. It's what's "protecting" the "protected" part of the legacy BIOS from being edited and still be "certified" for use with UEFI GOP. Which is why even with a corrected CRC, and/or 8-Bit checksum, UEFI GOP still will not work with an edited legacy BIOS(again, if the "protected" parts have been edited). Anyway, he fixed that so it doesn't get checked. And you can have UEFI GOP work now with an edited legacy BIOS("protected" parts edited). Though it's supposed to be limited to also using a patched atikmdag.sys file written for specific drivers(not really sure why on that one) and without being able to use Secure Boot(since the GOP module signature should be broken with the patch applied). I haven't encountered those limitations though. Which I can't explain...but is none-the-less cool! Works even better than it should!

I also found out that you can edit more than just the Device ID in the GOP module without breaking it(though the Device ID still needs to match the original Device ID of the card in question, as we previously learned). Which is a must to install a different GOP version(unless that version came from a card with the same original Device ID). You can also edit the AMD GOP REV: string. For some reason it's never filled out correctly. They just leave a bunch of x(s) and .(s) as the version number and build date. Which makes no sense why you would leave it like that. Maybe they were afraid of breaking it too. Anyway...I corrected that by inserting the proper info and it still works. Which makes sense, because why would there be space for it if you couldn't make use of it.

Oh and BTW...that whole thing about the microcode and how to make that work is discussed in thorough detail too. That I understand even less than the circumstances with my BIOS, which doesn't have that. But there does appear to be real solutions to the problem. At least in some cases.

 

[MrGenius]

I got a PM from @MrSpock asking to change the device ID of his HD 7770 to get it to boot with his M91P mobo. And since I can't post attachments in PM, and since the topic of the post is the same as this thread, I'm going to attach his BIOS edits here for convenience.

A little explanation as to what is what.

7770 to 7870 DevID 1st PCIR Only: I only changed the first instance of the device ID. But I don't know if that's enough to get it to boot. UEFI GOP boot might still work(though not very likely that it will, if it even boots at all).

7770 to 7870 DevID 1st & 2nd PCIR(Probably no UEFI): I changed both instances of the device ID. UEFI GOP boot probably won't work(though it still might). But it will most likely boot even if no UEFI GOP.

7770 to 7870 DevID 1st & 2nd PCIR + UEFI GOP patch: I changed the first instance of the device ID and used the UEFI GOP update tool(from the win-raid thread) to update the UEFI GOP to hellm's patched v1.63. Which also changes the 2nd instance of the device ID. It will most likely boot, and there's a decent chance that UEFI GOP boot will still work(though it might not). If UEFI GOP boot works it will be updated to the latest compatible UEFI GOP version too.

7770 to 7870 DevID 1st & 2nd PCIR UEFI Deactivated: I changed both instances of the device ID and applied the hex edit that deactivates UEFI GOP. It will most likely boot, but UEFI GOP boot will not work.

7770 to 7870 DevID 1st PCIR UEFI Removed: I changed the first instance of the device ID and removed the UEFI GOP section(and thus the 2nd instance of the device ID) from the BIOS image. It might(probably will) boot, but UEFI GOP boot will not work.

If you have any questions, or run into any problems, go ahead and ask them here. That way everybody learns something.

 

[MrSpock]

Thank you very much. Tomorrow evening I will start to try these. One question: can I apply these BIOS mods in my old computer under Windows (with atiflash) and then put it in the M91p to try it out, or should I use a bootable USB and do it in the M91p? Is there any difference in the process or in the result?

 

[MrGenius]

I would use your old computer under Windows. But the result will be the same either way. The process is the same as far as how you use atiflash. It's only different in how you get it to load. You'll have to run it in command line mode(using Command Prompt) under Windows since you're going to need to force flash it(because of the change in device ID). So in either case you'll need to enter the same command.

atiflash -f -p 0 Cape-Verde.rom

That hyphen in the file name puts it right at ten characters. So it shouldn't be a problem in DOS(since that's exactly the character limit). But if I'm wrong about that all you'd need to do is rename it. Actually I think I am wrong about that. I just googled it and what I found says a maximum of 8 for the file name + 3 for the extension. Anyway, what I do know for sure is, if the file name is too long it won't work(you'll get an error message). There's no such limit when running it under Windows though. Or rather the limit is considerably more characters(up to 32,767).

Everything else you would need to know to use atiflash to flash under Windows should be covered here:
http://www.overclock.net/t/1353325/tutorial-atiwinflash-how-to-flash-the-bios-of-your-ati-cards

Except that the latest versions of ATIWinflash will have a separate AtiFlash application in the downloaded folder that can be run with Command Prompt. I use that instead. But I guess you can use either. You would just have to change the commands accordingly.

 

[MrSpock]

Hello guys,

@MrGenius: thank you sooo much, I am grateful. Your mod totally worked!
I tried first and only the "7770 to 7870 DevID 1st & 2nd PCIR + UEFI GOP patch" BIOS mod. It booted instant, I auto-detected the video card with the AMD crimson relive minimal setup just to see whether it can detect the proper card. Also the GPU-Z sees it as original 7770. And yes the UEFI also works according to GPU-Z.
I attached a screenshot about it.
Thank you very much again!

And for the guys out there who were or will purchase an M91p rig: don't give! You only need to change the VGA device ID in BIOS !!

edit: i don't know why the pics don't appear, but here is the link via text: https://ibb.co/gMTr5G

 

[MrGenius]

GPU-Z just detects if the UEFI module is present, and/or activated. It can be present, and/or activated, and UEFI GOP boot may still not function. The way you know whether or not UEFI GOP boot is functioning or not is to enable it in the motherboard BIOS/UEFI and see if it works correctly when you boot. If it's working properly you won't get any error messages or black screen during boot. And booting will be significantly faster than without having it enabled. But since you're using Windows 7 you won't be able to get it to work at all as far as I know. I think you need to be using Windows 8 or later to be able to use UEFI GOP boot. I could be wrong about that though.

Also, the reason GPU-Z and other software still see it as an HD 7700 series is something I don't understand. Those programs are obviously getting that info from a part of the BIOS that I didn't edit. The only programs I know of that will now show the device ID as 1002-6818(HD 7870) are atiflash and VBE7. EDIT: I just checked and the UEFI GOP update tool will too.

 

[mcemsi]

Hi guys

Could you be so nice and make change for me from 1002-6611 to 1002-6758 (R7 240 to 6670) . Hope 6670 works in M91p