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I see that the modded Vbioses provided in this forum have been created by various forum members (making alterations to the original Vbioses of the cards). Thanks for the fantastic work.

Are these Vbioses modded to their full potential or could there be any improvement?

Meaning, could the Vbioses be modded/improved further? (i.e. to a specific iMac type) so as to perform better, more stable, fix sleep/wake issues etc.?
Or the modifications done to the original VBios is only to make the card recognisable by macOS, and nothing further can be done?

Unfortunately I don't have the knowledge for this.
 
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Also, can someone confirm this is the correct layout for the recovery CD? I cannot get the iMAc to boot from the recovery CD (pressing "C" right after switching on the iMac). I only get a black screen. Is there something I missed?
 

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trying to flash a K2100 but i get a "write protect" error in asprogrammer. how do you get around this?
 
trying to flash a K2100 but i get a "write protect" error in asprogrammer. how do you get around this?

I know how to do this only when flashing the card via ssh and terminal commands.
You need to run ./nvflash_linux --protectoff before you flash the new rom.

I have not used the asprogrammer. Does it have any option or check box that says "off protect before programming" or is there any "unprotect" button that you need to press before flashing the new rom?
 
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using asprogrammer V2.1.0.13. i have the box labeled "off-protect" checked, as well as the erase, write, verify. but when i click the program button this show in the message window and only the cancel X is lit up (all others greyed out).
Current programmer: CH341
Old SREG: 11111111(0xFF), 11111111(0xFF)
 
i have clicked the cancel button, which seems to have acknowleged the message above. green progress bar is roving back and forth with the following message, so ill wait awhile and see what happens.

Old SREG: 11111111(0xFF), 11111111(0xFF)
Canceled by user
Current programmer: CH341
11:45:29
Possible protection is enabled. Press "Unprotect" and check datasheet
Erasing memory...
The process can take more than a minute on large flash memories!
 
no luck, something to do with the registers i think. now i have upset it and everything i click on brings up a "choose item in the list" dialog box. very frustrating.
is there a different version or software i should try?
 
i think i got it! turns out the clip is extremely fussy. and has to be on just so. even when it looks like it connected it wont detect the chip. so after about 35 tries it finally detected and walked right thru the process of flashing Nicks K2100 bios. now i can reinstall into my 2010 imac and see if she boots up with Big Sur!
 
i think i got it! turns out the clip is extremely fussy. and has to be on just so. even when it looks like it connected it wont detect the chip. so after about 35 tries it finally detected and walked right thru the process of flashing Nicks K2100 bios. now i can reinstall into my 2010 imac and see if she boots up with Big Sur!
It's true, the CH341 clamp needs to be put perfectly on the chip. But I thought that you had got that right since if not, you cannot even read the contents of the chip.
 
Anyone else running Linux on a mid 2011 iMac 21.5"? It currently has a Radeon 6750. What is the best 'drop-in' GPU I can upgrade to if I don't care about Mac OS compatibility?
 
Anyone else running Linux on a mid 2011 iMac 21.5"? It currently has a Radeon 6750. What is the best 'drop-in' GPU I can upgrade to if I don't care about Mac OS compatibility?
Have you tried running linux with the amd 6750? Is it not working?

Personally I tried ubuntu with the k2100m (was not working OK), and now with the AMD m5100 (which works well).

Ofcourse I only tried with a live usb of Ubuntu 22.04. I have not actually istalled ubuntu. But everything was working good with m5100.
Also I suspect that you will need to flash the cards with the amended vBios.
 
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Also, can someone confirm this is the correct layout for the recovery CD? I cannot get the iMAc to boot from the recovery CD (pressing "C" right after switching on the iMac). I only get a black screen. Is there something I missed?
Anyone kindly assist with this? I cannot understand why I cannot get the iMac to boot off the CD. I believe that I have done everything correctly. Did I miss something?
 

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Have you tried running linux with the amd 6750? Is it not working?

Personally I tried ubuntu with the k2100m (was not working OK), and now with the AMD m5100 (which works well).

Ofcourse I only tried with a live usb of Ubuntu 22.04. I have not actually istalled ubuntu. But everything was working good with m5100.
Also I suspect that you will need to flash the cards with the amended vBios.
Yes, the 6750 is fine with Linux (Using Zorin OS) Sorry if I made it sound like it wasn't. I'm going to upgrade the CPU soon and figured I might try a better GPU since it will be tore down. But maybe only the 6770 is the only suitable replacement? Which wouldn't be much of an upgrade I suppose.
 
I spent some time last week changing out one of my kids 21.5" 2010 iMac video cards for a K1000m. I'll write up a detailed post later on in the week, but in the meantime I used the Winclone idea posted here earlier by FlorisVN to make a package installer Windows 7 Bootcamp so there is no need to install Winclone or do any other trickery. It requires 10.12 Sierra to begin, and it simply adds the bootcamp image to your internal hard drive on a 15GB partition it creates. Teamviewer has been installed, and the NVtools folder is on the desktop with the flash rom files ready to go. Also the Page file and Hibernate file have been pared down to 2GB each to avoid running out of space at 15gb. No bootcamp drivers were loaded to maximize portability. I tried this on a 2010 iMac 21.5 as well as a 2011 iMac 27" and they both worked perfectly for simply creating the bootcamp partition to use for flashing purposes. I also uploaded it to Sync which has unlimited downloads so it shouldn't expire or be pulled if it gets popular. Here's the link to download it, simply unzip the .pkg file and run it in MacOS 10.12 or higher.

Windows 7 Bootcamp pkg installer iMac
Good job jocaju!
Has there been an update to this method? I upgraded Nick [D]vB earlier and would like to upgrade the GTX 770M ROOM to 770M_BR+OC.ROM. How can I do this process through Windows?
 
Yes, the 6750 is fine with Linux (Using Zorin OS) Sorry if I made it sound like it wasn't. I'm going to upgrade the CPU soon and figured I might try a better GPU since it will be tore down. But maybe only the 6770 is the only suitable replacement? Which wouldn't be much of an upgrade I suppose.
If you want a plug n play solution (not flashing Vbios, keeping the oem boot menu etc.) better stick with the available options for the specific imac. Indeed I think that 6770m was the highest card for the 12.1 iMac. (I have the same iMac as you and it came with that card - 6770m).
If you will update the CPU make sure that it is an "s" variant. For example i7-2600s.
The "s" variants are the low wattage CPUs which is needed for the 21.5" iMacs due to the smaller PSU.
 
Good job jocaju!
Has there been an update to this method? I upgraded Nick [D]vB earlier and would like to upgrade the GTX 770M ROOM to 770M_BR+OC.ROM. How can I do this process through Windows?
Check the FAQ, use the GRML Linux tool!

Since you have a working internal display you can enter all commands directly sitting at your iMac. No second system needed, no ssh, no network trouble...
 
If you want a plug n play solution (not flashing Vbios, keeping the oem boot menu etc.) better stick with the available options for the specific imac. Indeed I think that 6770m was the highest card for the 12.1 iMac. (I have the same iMac as you and it came with that card - 6770m).
If you will update the CPU make sure that it is an "s" variant. For example i7-2600s.
The "s" variants are the low wattage CPUs which is needed for the 21.5" iMacs due to the smaller PSU.
Okay, thanks for the GPU info! I think what it has is fine as is for Linux. I will just re-apply thermal paste and call it good for another 5 years hopefully. I'm definitely keeping my eyes open for other 2011's that pop up on the local used market for spare parts on the cheap.

Regarding the CPU details you've mentioned; I looked at the TDP for Sandy Bridge Procs and saw that i7-2600s fits comfortably in the same range as the i5 this unit originally came with. Heat is always an important consideration. Especially with everything crammed in there. I guess maybe these 2011's do a decent enough job with heat dissipation being that they last so long, but I wouldn't want to stress the unit beyond reasonable tolerances.
 
Mid 2011 iMac 27 inch
AMD 6970M failed, upgraded to AMD WX3200 from Ali express, preflashed.
Installed in system, preinstalled with High Sierra. Ran but could only get to background & cursor after boot, no icons.
Upgraded to Big Sur 11.3 with OCLP, booted fine but did not have Wi-Fi/Ethernet. Chalked it up to a bad install.
Installed fresh Big Sur 11.5 using OCLP. Not sure if install was interrupted but I now have just a black screen on boot. Did not have boot chime until PRAM.

I realized the patch settings i made on my MacBook were right for the 12,2 but i did not pick the correct card family in the GUI as I was unable. I have downloaded TUI and can make change to GPU polaris but I still cannot access boot menu. ODD is disconnected. Did I f#%* my firmware? I did not backup my firmware originally as I was unable. I do not have a way to burn an OCLP recovery CD at this time.
 
Mid 2011 iMac 27 inch
AMD 6970M failed, upgraded to AMD WX3200 from Ali express, preflashed.
Installed in system, preinstalled with High Sierra. Ran but could only get to background & cursor after boot, no icons.
Upgraded to Big Sur 11.3 with OCLP, booted fine but did not have Wi-Fi/Ethernet. Chalked it up to a bad install.
Installed fresh Big Sur 11.5 using OCLP. Not sure if install was interrupted but I now have just a black screen on boot. Did not have boot chime until PRAM.

I realized the patch settings i made on my MacBook were right for the 12,2 but i did not pick the correct card family in the GUI as I was unable. I have downloaded TUI and can make change to GPU polaris but I still cannot access boot menu. ODD is disconnected. Did I f#%* my firmware? I did not backup my firmware originally as I was unable. I do not have a way to burn an OCLP recovery CD at this time.
No native boot menu using Polaris cards yet (the machine will just hang when trying to display the boot menu) - you have to use OCLP or disconnect any other bootable drives in order to force booting from the desired one.
 
No native boot menu using Polaris cards yet (the machine will just hang when trying to display the boot menu) - you have to use OCLP or disconnect any other bootable drives in order to force booting from the desired one.
I still have my OCLP/macOS installer usb drive connected, thought I could boot into that but no luck. The person I bought the card from also included EFI folders, so I have the one for Monterrey/Big Sur on a separate usb drive as well
 
Check the FAQ, use the GRML Linux tool!

Since you have a working internal display you can enter all commands directly sitting at your iMac. No second system needed, no ssh, no network trouble...
Thank's! I will study this method to do the procedure.
 
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