Cannot access grub menu on boot

[99available]

I am not an expert. So here goes.
I had Mint on my Apple MBP before, version 17 I think, I had to modify the grub file to add "modeset" to get my gpu to work (not get blank screen).
I switched to Fedora for a while but got tired of the hassles I was having with it.
Anyway I reinstalled Linux Mint 21. But I can't get the Grub menu so I can edit and mode the Grub file.
The current Grub file has GRUB TIMEOUT=0.
I can not get the grub menu by pressing escape or the shift key or any of the things recommended.
I used the Boot Repair USB to try and insert "nomodeset" and that did not work.
Using terminal through the Boot Repair I went to Grub on the device where Linux was installed, I was able to modify the Grub file to change TIMEOUT=5 and insert "modeset after quiet splash.
But when I run "sudo update-grub"
I get an error message about failed to get canonical path of /cow.
I tried POP OS and Ubuntu. All modern flavors of Linux seem to have the same problem
I just need a way to modify Grub and update it when the system won't boot. Like I said, in the past I get the Grub menu showing different versions of mint and I would click e and edit the grub and away I'd go.
Any suggestions are welcome, solutions more so, or just a flat you can't do that anymore and give up
I guess I could go back to an earlier Mint, but then will I ever be able to update it.

I have a 2011 MBP and yes it has built in Intel Graphics and a second AMD/Radeon card GPU card.

[gittiest personITW]

Welcome to the forums.

Here you go:
https://easylinuxtipsproject.blogspot.c ... b.html#ID8

[99available]

I finally was able to solve my problem:

I installed the latest Version of Ubuntu:

I tthen rebooted the system with my Boot Repair USB inserted.

I was given an option to boot from EFI disk or USB.

Booting from USB I got the boot repair screen. This time was able to successfully modified the grub file with the nomodest setting.

I rebooted after removing the USD and Ubuntu came up visible and running properly.

Mint must not be compatible with the Boot Repair program.

[SMG]

I tried POP OS and Ubuntu. All modern flavors of Linux seem to have the same problem

Yet now you say

I finally was able to solve my problem:

I installed the latest Version of Ubuntu:

So without versions on any of these, we have no idea what you tried or did, but glad to hear you are now happy.

[Reddog1]

Only the distributions that hide grub if linux is the only system installed, because the apple keyboard won't work (ESC) to bring up a hidden grub. I'm definitely confused as to how installing Ubuntu fixed the hidden grub, because Ubuntu hides grub, so I'm guessing you went at it another way, but it doesn't make sense that a boot repair disk wouldn't boot with Mint installed to HD.

Anyway, edit /etc/default/grub and unhide it with a timeout of 5 sec, in case something like this happens again. You shouldn't need boot repair if a future kernel update breaks your system.

MX linux does not hide the grub menu by default, when it is the only operating system installed.