Please @Maddeen post any changes you have found? I have just got this board
(but have not got time to look at it yet, but will install soon). I'm aiming at Catalina for a Photoshop workstation.
In the spirit of 'things moving forward' I will try out with OC. All tips, updates and upgrades are welcome!
Edit Mars 23:
Here you go, well working and stable Clover EFI folder for Cat. You might want to generate your own SSDT-USB.aml with Hackintool. No GTX980, only on-board iGPU graphics (no nVidia support for Catalina). I suppose hibernation & sleep isn´t working, I have not even tried. If somebody make sleep work, please post info here!
Edit Mars 29th
See my updated final EFI and BIOS settings.
'Everything' works: sleep, display off, native NVRAM.
You will have to change serials etc.
Catalina 10.15.4 (just clicked upgrade from 10.15.3)
iMac17.1
AMD RX560 GPU (consumes less power and is good enough for Photoshop)
NO GTX980 !
iGPU
is activated
SIP is unaltered
Boot sound works (really not important)
Hackintool says VDA is supported (not tested)
NVMe-disk as main disk
USB3.1 works (red connectors HSxx) - have not tested 'faster than USB3 speed' or charging
WiFi not installed
BT not installed
Thunderbolt - deactivated in BIOS. I don't need it
Sleep of mechanical SATA disk - can not test
I messed up and was caught in a Catch22 with USB settings. I solved this with boot arguments.
Please note: HS03,HS04,HS09,HS10,HS11,HS12,HS13,HS14,SS03,SS04 are deactivated. OSX prefer it that way. I have installed 2x USB3 connectors in front so internal HS01,HS02,SS01,SS02 are turned
on. You play with these boot arguments on your own...