- Nov 29, 2019
- Z170x-UD5 TH
- i7-6700K 4.00Ghz
- RX 5700 XT
OK. So I changed my install USB to version 10.15.2 instead of 10.15.1 (which was the installed macOS).You need a working EFI folder on your USB flash drive. Then, once you are booted in to macOS, you can replace the non-working EFI folder on your startup drive with the good one.
I'm still not quite sure on what the "magic recipe" is for RX 5700 (XT)s. Different users seem to require different settings.
Booted from USB and then choose Catalina disk form Clover.
Had to use terminal “sudo diskutil diskXsX to mount the EFI since EfimounterV3 only works in 32 bit.
I then took the EFI folder from USB and swapped it entirely with the previous folder since it had a lot of old stuff from my older build with GTX 960 4GB.
I then installed update 10.15.2 with a couple of reboots and waaaaay to long black screen periods (which scared me a little).
Now running 10.15.2 silky smooth. Wuhuuu!! Thanks for the pointer.