I was able to get mine going with full acceleration. I will need to make a log post to capture the extensive amount of time I spent figuring everything out on my build.
But to try and make it short for you I'll post my config.plist file so you can see what I have in there. I removed the SMBIOS Board serial number, serial number and SmUUID as you will have to create your own unique one.
The main things I had to do (all may, or may not be required but it works for me) in clover are below.
In clover configurator
>ACPI
-Fixes
-FixDisplay (checked)
-AddDTGP
-Under "Drop OEM_DSM"
-ATI
>Boot - All default including dark wake is set to "darkwake" and dart=0
>Devices
-Fake ID
-ATI set to 0X67EF1002 (to spoof ID as RX 460 to get GPU acceleration)
>Graphics
-ig-platform-id
-0a206080
>Kernel and Kext Patches (not sure if needed)
-ATI Connectors Patch
-Apple RTC
-Asus AICPUPM
-KernelPM
>SMBIOS ( I have it set to iMac17,1, not sure if this matters but I was using 14,2 and it works as well. Using 17,1 since it more closely resembles my build (i6700K Skylake). 17,1 works for me, no issues with black screen or other issues that I have seen around the forums here.
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I also edited the 4100.kext and replaced the ID 0x67FF in the info.plist to 0x67DF (should not needed if using the above clover ID that spoofs it for 0x67EF which is included in the info.plist file.
Using iHex I also did the "enable all core" mod.
Using iHex open the 4100.kext and change the following entries. As per this post:
https://www.tonymacx86.com/threads/enable-all-cores-r9-fury-cards.209892/
Do not use the values in the post though as they are for R9 cards, these are the right ones for our card:
Change number of CU's from 16 to 36:
48 B8 02 00 00 00 01 00 00 00 48 89 43 54 C7 43 7C 08 00 00 00
48 B8 04 00 00 00 01 00 00 00 48 89 43 54 C7 43 7C 12 00 00 00
Remove CU limit (didn't alter for P10):
0F 42 C8 89 8B 80 00 00 00 44 88 B3 99 00 00 00 44 88 73 20
90 90 90 89 8B 80 00 00 00 44 88 B3 99 00 00 00 44 88 73 20
Change init function to Ellesmere instead of Baffin:
E8 49 85 FE FF BE 48 01 00 00 4C 89 F7
E8 46 E4 00 00 BE 48 01 00 00 4C 89 F7
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I also booted into windows and modified my card's bios using Polaris bios editor to set a lower voltage at 1290 MHz (1000mV). My card was throttling under macOS with factory bios and couldn't sustain itself running Unigine Valley. I also increased the power limit by 10%. I then flashed the custom bios back ( since the new values are in the bios they work under macOS).
(note that editing your bios will make windows amd crimson flag it and not load the drivers in windows, you will have to patch some files for it to work in windows (look up AMD bios check bypass).
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Another thing I had to do to get sleep/wake to work was to plug in my monitor to my motherboards Display Port. This causes it to be used for the pre-boot sequence. but does not show as connected under macOS. This gives me only the RX 480 under macOS and sleeps/wakes perfect.
When I used my motherboard's HDMI port it would be recognized as a second monitor in macOS and would fail to wake/sleep.
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This may or may not be needed but since I will NOT be using my iGPU at all only the RX480 I removed the following 2 files from /System/Library/Extensions I believe they keep the Intel HD 530 SKL CRB driver from loading. I removed them as a redundancy for Final Cut Pro X, so that it would only load the AMD RX 480 as GPU. With these files removed your iGPU will show image but it will be like in 8bit color and missing all sorts of colors but still usable for troubleshooting if ever needed.
-AppleIntelSKLGraphicsGLDriver.bundle
-AppleIntelSKLGraphicsMTLDriver.bundle
