Istalling Ubunto on a Mac, Ubuntu 20.04 Failed to Set MokListRT: Invalid Parameter
Solution 1:
I resolved this by booting from the Ubuntu installation media again.
First Select the try Ubuntu option on the startup menu and wait for the OS to load.
Launch the disks utility from the applications menu and find the Ubuntu boot volume, the partition type should be labelled EFI system. Click on the cogwheel to open the partition options menu and select Edit Partition. Under here you will need to tick the box called legacy BIOS bootable.
Once you have done this remove the installation media and reboot the computer.
If all goes well Ubuntu will load correctly.