Minimal GRUB command-line on boot

[defaultcitizen]

Yes, I have the latest UEFI from ASUS. I upgraded it recently for RAM testing purposes, default settings were loaded and the problem began.

I've checked the motherboard UEFI manual and there isn't any password settings that I've use or are on by default. My board is the ASUS PRIME Z690-P D4.

Secure Boot does have these options:

Secure Boot Mode
This option allows you to select the Secure Boot mode from between Standard or
Custom. In Custom mode, Secure Boot Policy variables can be configured by a
physically present user without full authentication.
Configuration options: [Standard] [Custom]

In this case, it's set to Custom. This enables some key management section that I've left untouched.

I'll try using the --no-nvram option for grub-install, from the Live USB.

[defaultcitizen]

I ran this command while running the Live USB

ls /sys/firmware/efi/efivars

and it generated lots of output. So that means the USB is running in UEFI mode?

However, I'm not sure to proceed.

kubuntu@kubuntu:~$ sudo su - 
root@kubuntu:~# modprobe efivars 
modprobe: FATAL: Module efivars not found in directory /lib/modules/6.5.0-9-generic
root@kubuntu:~# mount -t efivarfs none /sys/firmware/efi/efivars 
mount: /sys/firmware/efi/efivars: none already mounted or mount point busy. 
       dmesg(1) may have more information after failed mount system call.

[oldfred]

The efivars is mounted in mount command, so one of default mounts.

efivarfs on /sys/firmware/efi/efivars type efivarfs (rw,nosuid,nodev,noexec,relatime)

I also get error on modprobe in Kubuntu 22.04. Not sure if in past it was in kernel & either Boot-Repair or grub use that to confirm UEFI vs old BIOS?

[defaultcitizen]

I'm still not sure how to proceed with this manually.

sudo mount -t efivarfs on /sys/firmware/efi/efivars type efivarfs (rw,nosuid,nodev,n
oexec,relatime)
bash: syntax error near unexpected token `('

sudo mount -t efivarfs on /sys/firmware/efi/efivars type efivarfs
mount: bad usage
Try 'mount --help' for more information.

At this point I'm considering a temporary workaround.
I think I will set Windows 11 to be first the boot order to bypass GRUB and use the boot menu (pressing F8) on reboot to gain access to Kubuntu.
I've done something similar in the past, so I assume it's fine for now, especially with my light usage compared to Windows.