We need to use the DEBUG build of OpenCore.efi. Download the DEBUG build from here.I tried and nothing change. I downloaded again the debug version and replace the OpenCore.efi unsuccessfully. It not registered nothing about IMMO. I triying to find a solution but it pretty wird.
Regard
When you unzip the package, just locate OpenCore.efi from here:
Rename your existing OpenCore.efi to something like OpenCore-RELEASE.efi, then copy this DEBUG version into the EFI partition (EFI/OC folder). Reboot and then MMIO entries should be present. Afterwards you may delete the debug OpenCore.efi and rename OpenCore-RELEASE.efi back to OpenCore.efi