[ubuntu] Failed to set MokListRT: Invalid Parameter - I am scuppered!

Hi all,

Really need some help.

I installed Ubuntu 20.04 LTS 4 days ago on an iMac 2008 with Mac OSX 10.6.8 Snow Leopard, as I'd heard was a fantastic upgrade I wanted to try.

Installed from USB.

First install= no wifi access; I ran software updates inside Ubuntu. Fixed wifi. Then Firefox froze desktop. Needed reboot.

On this reboot I got the following message, which persists. Sometimes boots to Ubuntu, sometimes just this message on screen and not further.

If I hold alt + R on powering up, I get a picture of EFI drive or Time Machine Drive (which is the only drive plugged in). I cannot boot my Mac OS :0(

I have checked the forums; there is one post of the below. Only resolve is a BIOS issue on a Dell machine but nothing else.

I'm not a coding / terminal expert, I'm a paramedic and want my Mac back. Please help!

"Failed to set MokListRT: Invalid Parameter
Could not create MokListRT: Invalid Parameter
Importing MOK state has failed: import mok_state() failed: Invalid Parameter
Continuing boot since secure mode is disabled"

Thanks everyone,

Mickie x