I found the solution. Finally.
The main issue is: in EFI in the folder OC/Kexts/AppleUSBTopCase.kext/Contents/PlugIns/ the file "AppleUSBTcKeyboard.kext" was missing after booting Linux, but instead I got an additional "FSCK000..." folder.
Not 100% sure but it seems that Linux did some scan and...
I just yesterday in the evening found the seemingly real reason. I will try to get it fixed today/tomorrow and post an update for if other tinkerers experience the same pain! :D
Update: No luck. Tried several things:
- Installing mint via "ubiquity -b" ergo without boot loader => no luck
- In Linux "sudo systemctl disable systemd-boot-check-no-act.service" => failed.. does not exist, since I got no boot loader
- In Linux "GRUB_CMDLINE_LINUX_DEFAULT="quiet splash...
I had somewhat of the same issue you had in your second point!
I got Sequoia running on my 2013 MBPr with the latest OCLP 2.4.1.
Now I wanted to parallel-boot Linux MINT.
What I did was partition the drive 50/50, install Linux MINT on the 2nd half but with "other" method, writing the boot loader...