Got a tip for us?
Let us know
Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.
iM 4,1-14,4 EnableGop: Pre-OpenCore GOP support for EFI-era iMacs and Mac Pros
- Thread starter Bmju
- WikiPost WikiPost
- Start date
- Sort by reaction score
- Status
Have you been able to use the vbiosinsert script with the hp rx 460 2gb gpu? I am getting the AMD size limitation error?
There's a success report for this card here, but I think it's for a MacPro with EnableGop in main firmware. If you are on a MacPro, that is probably your best bet. If you are on an iMac (is there even an MXM format RX 460?) or even if not, you can try asking on this thread if anyone has (or could make) and RX 460 rom without the legacy bios.
Dear friend ,Did you have sloved this problem :
k2000.rom add EnableGOP.efi failed things??I notice that
@armdn have report this things
EnableGop: Pre-OpenCore GOP support for EFI-era iMacs and Mac Pros
Well, this is strange... For the Quadro K600 ROM Auto-detecting GOP offset... Compressing EFI using EfiRom... Adding Nvidia header... Combining... Verifying (starting at 0xF400)... Found compressed EFI ROM start at 0x4c Input size: 110004, Output size: 11967, Scratch size: 13376 UEFI...
forums.macrumors.com
Auto-detecting GOP offset...
Compressing EFI using EfiRom...
Adding Nvidia header...
Combining...
Verifying (starting at 0xF400)...
Found compressed EFI ROM start at 0x4c
Input size: 148404, Output size: 13393, Scratch size: 13376
UEFI decompression failed!
I never got a reply to my post asking for a ROM to test, so dropped this issue. If you send a ROM with this issue, I can take a look.
Here is the K600.rom and K2000.rom,also has the same error :UEFI decompression failed!
GT610.rom use nvflash backup from a real card;k600.rom and k2000.rom download from
@armdn reply;I did not flash the “EnableGOP gt610.rom ”into the real card,because it shows error:UEFI decompression failed!
May cause a black screen?
without looking at the details: I have made for k600, k2000 and k2000d roms with EnableGop.
Just by using the provided script. I am not the GPU rom guru
And, no, you should not fetch a prebuilt GPU rom, there are various versions with 3 kinds of GRam of those Quadro GPUs on the market. And countless firmware versions. It's dump your GPU and patch it.
I had a lot of Quadros in my hands as I like this little beasts, especially as they provide a DP output, and some mDP like the K2000d.
...Or patch the Mac firmware, what imo is way easier.
Just by using the provided script. I am not the GPU rom guru
And, no, you should not fetch a prebuilt GPU rom, there are various versions with 3 kinds of GRam of those Quadro GPUs on the market. And countless firmware versions. It's dump your GPU and patch it.
I had a lot of Quadros in my hands as I like this little beasts, especially as they provide a DP output, and some mDP like the K2000d.
...Or patch the Mac firmware, what imo is way easier.
Thanks for the additional info.
Correct, do not flash after 'UEFI decompression failed', it very likely will cause a black screen, and need to reprogram the card using hardware (e.g. CH341A plus SOIC clip).
I was trying to add the Mac Boot Screen support to my AMD Radeon Pro WX7100 (PCI-E) card on my Mac Pro 4,1/5,1 but constantly get the "- Not enough space within 128k limit - aborting!" and I have tried all EnableGop 1.0 - 1.4. I read the "Deleting the VGA" Github instructions twice and played around with it but honesty it felt like I was taking my final in Organic Chem again, Lost. I thought I knew what I was doing until I had to. Let's just say it's been a long time since I used a hex editor. If someone would help point me to exactly where I find the "atomdis" tool? and any help with where exactly is the area were I can delete the VGA section, I think I can figure it out but HEX Fiend keeps freezing in Ventura. So any advice on other editors that will work with the template from Ausdauersportler? I attached my rom file (262 KB) unzipped, in case anyone wants to peek and let me know if it is even doable or am I just wasting time. I also downloaded some of the roms from iMac WX7100 but it was like comparing apples to oranges. That did not help point me anywhere with the PCI-E card. Thanks in advance for any help.
Why not just install EnableGop to your boot rom instead of the GPU?
Hi Lance, I did to my wife's Mac Pro also to her RX480 and will to mine once I get this card done. I swap my cards oftentimes into Mac's I repair for friends and family and the occasional repair customer (side gig) it's nice to have a single slot card to use for that. Figured since I'm likely to upgrade soon to an RX6600 this could become my diagnostic card especially since support goes back to High Sierra. It's only 125 watts max and works fine off 1 pci-e mini 6 pin and the bus power. That said when diagnosing Macs you sometimes need that good old boot screen and If it's not my Mac I'm not doing anyone's ROM upgrade. Just in case something goes wrong. If it can't be done it's fine but figured it be useful for my side hustle and for a little bit of learning too.
EnableGop targets the most recent MP5,1 (or MP4,1 upgraded to 5,1) firmware, and may not (probably won't) work and may cause the machine not to boot (while the card is in), if it has earlier firmware.
I just checked Lance's
On my GPU it is written: SAPPHIRE PULSE RADEON RX 580 4G GDDR5 DUAL HD MI/DVI-D/DUAL DP OC W/BP (UEFI)
How do I know:
- Does my Radeon RX 580 come with "dual BIOS" or not(physically there is no switch unlike my friends NITRO model).
- And if mine is still with dual BIOS, how can I be sure I have it switched on "gaming mode" or "full power mode"?
How was your experience? Did you had to do anything extra or you just "did the enableGOP without extra moves"?
If the GPU provides a bootscreen with OpenCore it should provide one with EnableGop.
If it does not give a bootscreen with OpenCore than it may have no valid GOP. So that's your path to follow. Maybe someone modded the GPU firmware for mining.
I am aware knowing a dual bios GPU without a physical switch, if it has none it is no dual bios GPU.
Edit: switch position for RX580 pulse: https://www.techpowerup.com/forums/...se-stock-bios-and-modification-advice.296675/
Last edited:
Hi @jeanlion - I'm trying to get some more time to look further. I did get as far as reminding myself of the basic issue, which I described here before, and I can see again in the ROMs you sent me.Hope@Bmju have a good news
I can tell you one thing that would help to save time, please can you confirm which of those ROMs already work if burnt to the relevant cards in question (i.e. at least show graphics in macOS), and which of them already work in OpenCore (i.e. show a graphical boot picker, after configuring OC)?
As explained in p.1 EnableGop only works for cards which are known to basically work in OpenCore - it is part of the OpenCore project, and uses various parts of OpenCore's GOP handling to work.
For cards where you can 100% confirm that the ROMs you have currently sent already work fine with that card in OpenCore and show a graphical picker menu, then I'm happy to carry on the work and try to figure out how to make the EnableGop insertion script support them. If any of these are ROMs which you picked up which are not yet confirmed to burn, boot, and work in OpenCore for a graphical menu, then please do check! (For any which you extracted yourself from a card known to work for a graphical menu in OpenCore, and any which you downloaded but have already burnt to the card and the result worked for a graphical menu in OpenCore, that is fine - and those are the ones I am happy to work on!)
Last edited:
I'm a long-time Mac Pro user and first of all I want to thank the experts here for the enthusiasm, expertise and time they invest in allowing this community of ours to enjoy these wonderful machines for so long. I don't think Apple has ever made a computer as good and long-lasting as the 5,1. And they probably won't do it again because they would go bankrupt.
I read these instructions carefully, saved the current Mac ROM, injected EnableGOP, tested the new ROM, everything seems ok and quite routine. The last step is to get into firmware mode and flash it to the motherboard. And here I get into unexpected sideway: when I restart Mac Pro into firmware mode (flashing, long beep) it continues to boot but after a while it just stops and restarts (of course not in firmware mode any longer). Before that I disconnected all drives except the boot drive (NVMe) so it's not that it could boot to some wrong OS.
I am on latest OCLP 1.3.0 with current Sonoma 14.2.1, system is perfectly stable daily work horse. Any idea what is happening? Is it a good idea to make one clean Mojave drive and try the procedure without OpenCore? Any other way to force firmware boot?
I read these instructions carefully, saved the current Mac ROM, injected EnableGOP, tested the new ROM, everything seems ok and quite routine. The last step is to get into firmware mode and flash it to the motherboard. And here I get into unexpected sideway: when I restart Mac Pro into firmware mode (flashing, long beep) it continues to boot but after a while it just stops and restarts (of course not in firmware mode any longer). Before that I disconnected all drives except the boot drive (NVMe) so it's not that it could boot to some wrong OS.
I am on latest OCLP 1.3.0 with current Sonoma 14.2.1, system is perfectly stable daily work horse. Any idea what is happening? Is it a good idea to make one clean Mojave drive and try the procedure without OpenCore? Any other way to force firmware boot?
I'm a long-time Mac Pro user and first of all I want to thank the experts here for the enthusiasm, expertise and time they invest in allowing this community of ours to enjoy these wonderful machines for so long. I don't think Apple has ever made a computer as good and long-lasting as the 5,1. And they probably won't do it again because they would go bankrupt.
I read these instructions carefully, saved the current Mac ROM, injected EnableGOP, tested the new ROM, everything seems ok and quite routine. The last step is to get into firmware mode and flash it to the motherboard. And here I get into unexpected sideway: when I restart Mac Pro into firmware mode (flashing, long beep) it continues to boot but after a while it just stops and restarts (of course not in firmware mode any longer). Before that I disconnected all drives except the boot drive (NVMe) so it's not that it could boot to some wrong OS.
I am on latest OCLP 1.3.0 with current Sonoma 14.2.1, system is perfectly stable daily work horse. Any idea what is happening? Is it a good idea to make one clean Mojave drive and try the procedure without OpenCore? Any other way to force firmware boot?
The easy path would be booting into Mojave,
You can flash the firmware with Linux, I have a grml thumb drive with Flashrom on it if the Mac is booting no Mac Os no more.
Another path, if nvram is havoc is booting into Mavericks with the RTC battery pulled.
I guess you have checked the health of your dump. Also check RTC battery, should read at least 3.0 volts with a multimeter.
Tnx! I checked it, no errors, no Microsoft garbage, VSS1&2 healthy and I have 9243 bytes free space of 65464, is that enough to add EnableGOP? I guess RomDump will tell me if there is not enough? But let's cross that bridge later...
Thats free space in the active nvram stream. Its a circular log, gets filled with every boot / wakeup from full hibernatemode 25 sleep, until close to empty, gets cleared and filled again. This is happens about every 8 to 16 boots, regarding how many's variables the system and the firmware writes.
EnableGop is injected elsewhere, we have plenty space for firmware modules.
As your machine acts strange I would not take the risk to flash in Sonoma, even if you get it to boot in Firmware unprotect mode.
Better run a supported OS without OpenCore. And do a deep nvram reset before, holding alt-cmd-p-r until the box chimes 4 times to clear as much of the nvram as you can.
Something is strange. I also would reduce the hardware to as less as possible what’s needed to boot the machine in a supported OS.