Installed but stuck at, “this Mac needs a firmware update in order to install to this volume”

Hi Team,

Here’s my system info:

CPU: Intel I9-9900k (microcode 906EC)

Primary GPU: AMD RX-580 (8GB)

Secondary GPU: iGPU from motherboard (set to remain active)

RAM: 48GB

Motherboard: AS Rock Z390 P1.4 (VT-d enabled, SGX enabled, Above 4G decoding enabled, XHCIHandoff=enabled)

nVME: 1TB Samsung EVO 970

Guide Followed: Dortania Guide

OpenCore EFI: 0.6.3

I’ve worked through the guide, used the utilities & guides to build my SSDTs, kexts, etc. per the coffee lake section of the install guide. (I didn’t use a pre-built config)

I used GenSMBIOS with iMac19,1 for the config template. Using the sanity check page, I got all green check marks for my config.plist.

I had some issues where it got stuck during the boot phase, but managed to figure out the right BIOS settings to make everything “happy”. (it was the USB hand off that was getting stuck)

It now “boots” and I’m able to format my nVME drive using the disk config utility with APFS. I can run a terminal shell, and the APFS volume is mounted and everything seems to be ok.

When I try to install Catalina on that drive however I get an error message saying that my Mac needs a firmware update in order to install to the APFS volume. I’ve tried installing to a MacOS Extended volume but Catalina didn’t like that either.

I’ve searched the googles and this subreddit, but didn’t find anything that worked. I’ve tried re-generating my GenSMBIOS with iMac19,2 but that didn’t work either.

I read that iMacs might want the internal iGPU active, so I set that to be active in the BIOS but that didn’t seem to make a difference.

I can mount apple volumes using the disk utility, and open them up using the terminal shell, but I just can’t convince it to install to that drive.

Any thoughts? Thanks!!