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dortania / OpenCore-Legacy-Patcher

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https://dortania.github.io/OpenCore-Legacy-Patcher/
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5k Output issues on iMac15,1 (27" 5k iMac - 2014) #359

Closed khronokernel closed 2 years ago

khronokernel commented 3 years ago

When booting OpenCore on an iMac15,1, the iMac's firmware will enforce a 3840x2160 resolution on the internal display. This seems to be an unfortunate issue with the 5k iMac series as the issue plagued Windows, Linux and UEFI. Apple eventually made a driver hack for Windows however both UEFI and Linux fixes are missing.

Work-Arounds

The only current solution to restore 5k output is to boot macOS without any 3rd party boot loaders. However this therefore breaks OTA updates, AirPlay to Mac, Universal Control and other patches. Additionally forcing a higher resolution within macOS only emulates 5k, the actual screen resolution stays at 4k.

As we have no hardware locally, we cannot continue researching. Hardware donations would be appreciated, see Supporting the patcher page for more information.

Thanks to the gracious donation from @turbomacs we have a 2014 5k iMac locally now! Currently research is being done and patch sets developed.

Working solution can be found here: https://github.com/dortania/OpenCore-Legacy-Patcher/issues/359#issuecomment-988417731

Associated branch: 5k patch

Issue will be closed once patch set is merged into mainline.

Additional Information

Original Issues Thread:

owenzhao commented 2 years ago

iMac15,1 Research: First Public Test

So after cleaning up the patch set a bit, we should be good to test our first public build. As expected, ensure you have a native OS you can return to in the event the build has unexpected issues.

Binary below is based on the 5k-display branch (commit fd26627)

Note: Github artifacts require you to be signed in to download.

I downloaded the binary at the link. Build and install the patcher in the internal SSD. However, after I reboot, nothing happened. It seemed that I was not installed anything.

I had debug verbose to true. Any idea?

I was hoping to test native resolution issue so I thought it was OK to use macOS 11.6.1.

iMac 5K 2014 Late, macOS 11.6.1 (20G224)

Howe could I know if I have successfully installed this patcher?

gunmall commented 2 years ago

The new public patch is working perfect on iMac15,1. So cool. Thank you so much for your work. Screenshot_01

SofteqDG commented 2 years ago

@khronokernel, Thanks a lot for your work! First public build with 5K support works like a charm! iMac15,1_OCPL_Monterey21,1

No new issues was detected after a small test. Before installing this test build i've cleaned nvram and removed everything from /EFI volume.

owenzhao commented 2 years ago

@khronokernel, Thanks a lot for your work! First public build with 5K support works like a charm! iMac15,1_OCPL_Monterey21,1

No new issues was detected after a small test. Before installing this test build i've cleaned nvram and removed everything from /EFI volume.

What did you do? After I booted and chose EFI, all I got was a blank black screen. I just installed the patche to SSD EFI and chose booted from EFI. Any more I should do?

SofteqDG commented 2 years ago

@owenzhao, I don't use picker. Update process for me was:

  1. Change back resolution of the display to "Default for Display"
  2. Clean nvram with sudo nvram -c in Terminal
  3. Remove everything from EFI partition (with hidden files)
  4. Install new public test build of OCPL
  5. Turn off and turn on iMac
  6. Be happy with 5K resolution :)
viking1304 commented 2 years ago

I have a strange issue with this test build on iMac18,3

After I select that I want to boot from EFI

image

I am getting this

image

If I try to boot EFI I am getting blank black screen (even with -v boot argument in config). I will try again later after I finish with work.

@owenzhao since you have similar issues, this might be related to specific iMac model. What is your exact model?

herrfisk commented 2 years ago

Is this in the official build yet or is it in beta? I notice that the issue is still present on https://dortania.github.io/OpenCore-Legacy-Patcher/MODELS.html#imac

owenzhao commented 2 years ago

I have a strange issue with this test build on iMac18,3

After I select that I want to boot from EFI

image

I am getting this

image

If I try to boot EFI I am getting blank black screen (even with -v boot argument in config). I will try again later after I finish with work.

@owenzhao since you have similar issues, this might be related to specific iMac model. What is your exact model?

I have got mine machine work now.

截屏2021-12-08 下午7 26 00

For the black screen issue.

That was because of the second EFI, you should never chose that. You should first choose EFI Boot, then chose the installer or the macOS you wanted to use. If you chose EFI again, you got a black screen.

If you don't want to use this patcher, you should choose the macOS menu along with EFI boot menu. So clearly the second EFI should never be chosen and should not be shown as a menu at all.

Good luck!😊

ElreboCM commented 2 years ago

I can confirm it is also working for me.

However, there is one caveat with the method atm: Keyboard Layout is English although I have set it to German.

khronokernel commented 2 years ago

iMac15,1 Research: Public Test Build 2

Cleaned up the OCLP build process as well as ensure that no "mysterious" EFI BOOT entry appearing in OpenCore's menu for users to accidentally select.

Binary below is based on the 5k-display branch (commit f75f1aa)

mth75 commented 2 years ago

Works on my:

Screenshot 2021-12-08 at 19 53 00

Thx mate!

I was running Monterey already so I now :

a. Build Opencore again b Installed Opencore to Internal drive (overwrote the EFI partition). c. rebooted ...

done!

khronokernel commented 2 years ago

So after some extensive testing, can comfortably say this new digs.efi chain loading should be quite reliable. I have merged this into mainline earlier today:

We'll likely do a new release for OpenCore Legacy Patcher later this week once we have the remaining cruft cleaned up.

But otherwise we can finally consider this issue closed! I have summarizing my research and development of this thread on my blog for those interested:

Finally I wish to say thank you again to @turbomacs for offering to both send and cover shipping for this beautiful 5k iMac all the way to this frozen land of Alberta, Canada. Without their extremely generous donation, I don't believe I would have been able to get so far!

herrfisk commented 2 years ago

Remember to update the "Supported models" page that this is now fixed

Caesar113 commented 2 years ago

I used the latest OpenCore release to upgrade my iMac 15,1 Big Sur installation to Monterey 12.1 last night and it went seamlessly! Many thanks!!!

ragian commented 2 years ago

I'm trying to install the Monterey 12.1 but after a while a black screen with a folder with a question mark inside it is showed. Any advice?

herrfisk commented 2 years ago

I'm trying to install the Monterey 12.1 but after a while a black screen with a folder with a question mark inside it is showed. Any advice?

Yes this happened to me as well. It’s because during reboots the computer boots from the regular, unpatched EFI. You need to boot and hold down the option key and choose the open patcher EFI and then your hard drive. The computer will restart a couple of times during the process so if you get stuck on this ore some other error you have probably booted to the unpatched EFI. Just reboot and hold down option

turbomacs commented 2 years ago

Wow that was fast! So happy I could help keep so many perfectly good Macs on the road a few more years! Happy holidays and happy new year everyone! Keep paying it forward!