Now I try to upgrade from 12.0.1 to 12.1 and I face same problem. The hackintosh starts the Mac OS Installer then stops and reboots. I try several time and nothing seems to happen.
Last seen message : "We don't support SMC on this platform"
This was the same for me too.I had to change SecureBootModel value from Disabled to the one corresponding to my SMBIOS profile in order to see the update. Once the update started downloading, I changed the value back to Disabled.