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Mr-Mur

macrumors member
Original poster
Jul 4, 2018
50
25
Hi there!

As many others, I performed a GPU-upgrade to my 2011 27'' iMac: GTX 780M replaced a stock 6700M.

No drama, works well when High Sierra startGUI, just got no boot-screen and completely lost brightness control (weel-known issues per say).

I used to view all relative topics and messages, especially in profile topic, but anyway, the only solvation so far is a special UEFI ROM for GeForce cardm compatible with Apple.

But cMP users trying using special bootloaders and some say - there is a few successfull installation.

According to this, I tried to install the Next Loader yesterday, because it can initialize GOP-graphics card (I hope my GPU supports it).

I inserted my 16Gb USB-flash, ran sudoed ./install.sh, chose installation onto flash. But, unfortunately, no luck: after rebooting Mac OS loaded from my internal SSD. Neither Boot Manager.app and System preferences Boot applet did not recognize my USB drive as bootable.

Also, before replacing stock ATI-card, I installed Windows 10 to Bootcamp HDD-partition (with this method to support sound card), it works well, but with GeForce I even cannot start it! Got just black screen at all.

I did not try rEFInd with a GOP-support, mainly because it should install onto main boot drive (not USB flash).

But I am still sure, these bootloaders can really help us boot iMac with boot screens etc.

What do you think?
 
I installed booted via stock installer.sh onto my USB flash drive.
Tried booting at my MacBook Air with Option pressed, this EFI section loaded successfully, Next Loader's GUI appeared well.
But iMac refused to boot to USB drive, High Sierra loaded instead GUI.

I cannot see this USB drive at Boot applet, is it correct?
Снимок экрана 2018-08-26 в 21.18.30.png
 
I think you dont get a screen, because your gpu doesnt support modern GOP.
Maybay you can modify your 780m bios to apply GOP...
 
I think you dont get a screen, because your gpu doesnt support modern GOP.
Maybay you can modify your 780m bios to apply GOP...

Unfortunately, I cannot even boot to Windows 10 (already installed via Bootcamp) to launch GPU-Z to find EFI checkbox :(
And also there are no laptop with MXM-compatible card nearby

But I noticed the strange thing: I inserted my USB-flash with a Next Loader into Macbook Air and it booted GUI! Pressing Space key I got bootloader's startup menu, not Apple's stock one!

But in iMac I wasn't able to get booting paused, maybe iMac insn't able to boot my flash? Strange issue, isn't is?
 
your GPU needs GOP otherwise it wont display the Next Loader bootloader...
 
have you managed to get the Next Loader to work yet.. ?
Or have you maybay managed to mod you bios to get GOP support in it.. ?

I'm wondering how to progress is going..
 
have you managed to get the Next Loader to work yet.. ?
Or have you maybay managed to mod you bios to get GOP support in it.. ?

I'm wondering how to progress is going..

No… I currently removed GTX card to stick 6770M… Let us see if any ROM news appear
 
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