Hello all,
I recently purchased a late 2009 iMac 11,1 with some damage from a posting on a local site craigslist.com for cheap. I have repaired all the damage, the lcd display ribbon cable had been ripped off, pulling a few pads, luckily I was able to trace back to vias the pads were connected to, clean them off and solder the whole lvds cable to the logic board. There were a couple problems with this, white screen only, no boot from hdd or snow leopard dvd, only 2 diagnostic lights illuminated. Popped the gpu in the oven and reflowed, got 4 lights but still no boot. disconnected hdd and option key would show mouse cursor. popped in ubuntu 10.04 cd and got blinking cursor on black screen but nothing else, got me thinking and popped in windows xp cd and it booted, popped in win7 and viola installed fine (it would not boot if I selected efi with the cursor, but would when I selected "windows", still dont know whats up with that...)
Anyway I upgraded the cpu to an i7-870 (the 880 was a tad spendier for not much performance improvement) and purchased radeon hd 7970m as I wish to use this machine as a replacement for my current acer laptop with a 5650. crysis 3 runs only 20-40fps at minimal settings, titanfall does about the same but the card in the imac only has dx 10.1? double the shader cores and none of my games are playable... Anyway
so here I am, have an imac with windows 7, no efi boot and a 7970m gpu that it refuses to post with.
I have reviewed the MXM3.0 spec and if apple adheres to it, there should be no reason other than video bios/logic board bios why it would not boot.
I have probed around and we are getting power, the gpu should be operational but logic board powers it down after I'm assuming it reads info from rom and is not pleased with what it sees.
the video card is an alienware dell 7970m with 15.022.000 rom. Pm25LD010 128k? spi flash (according to my flash programmer, datasheets found online say 512k??)
existing video card had Pm25LV010 flash, also 128k, I have compared it with the apple 6970 looking for similarities and there are quite a few among the 3
the only main difference I can tell is the extra data after the 0xFF's and a handfull of missing or added data between them, there are a few contiguous chunks here and there that have changed, I can't tell what was apple's doing and what is due to architecture differences. wimbledon is fairly new but I was surprised to find so much in common between them.
Thus far I have tried:
Changing the vendor ID in the bios portion of the rom w/corrected checksum - still no boot.
I'm not sure if the gpu not getting 11.9v instead of 19v is an issue, but according to the mxm spec, it should be fine between 7-20v
I was in contact with macvideocards via email and he discussed with me how to get it going with osx after I get it working, and the difficulty of creating the efi bios for this creature, if anyone here has any tips/details that would help this project along it would be magical! I have yet to delve into the magical world of atom bios disassembly and the thought of it gives me frownie face but if it comes to it, I'm fairly dedicated and have some resources at my disposal. I'm sure this would be music to the ears of anyone else that wants this to happen, once more my relentless google searches involving imac and 7970m brought me only sadness and hints of mac pro.
Attached is the important stuff from my conversation with macvideocards:
The part below means vendor id of 1002 with device id of 6800
And as we can see in the AMD 7000 controller, that device id exists
so it “should work” minus boot screens
writing an EFI for it will be very tricky as there was never an iMac with 7xxx was there?
You should be posting all of this at Netkas or MR or TechInferno (if you aren’t already)

> On Dec 3, 2014, at 10:14 PM, Nicholas Kruft <
kruftindustries@gmail.com> wrote:
>
> 02 10 00 68