issues with boot on a MacBookPro

Hello Ubuntu World

I have a MacBookPro (MBP) late 2011 (core i7 with 4GB RAM 512GB SSD).
Since more than a year I use it with Ubuntu Mate (20.04.3 and now 22.04.1) and no Mac OsX present (the latest supported is High Sierra 11.6).

For now more than 2 month I encounter problems during boot.

It works ... but not always ... on a non predictable way!

Following the recommendations of the forum I installed rEFInd

Sometimes my MBP refuse to boot via rEFInd
sometimes it works after 2-3 trials,
sometimes he boots via grub ......
sometimes it dumps (see screen image).

I always start pressing the alt key and select to only boot device present (EFI boot)

Once started everything works fine and I'm very happy ... so I avoid to reboot
Does someone have the same problem or a idea for solution?

Thanks a lot for your help

PS: I even tried to reinstall MacOsX via the internet but it doesn't work :-)

Attached Images

• boot_dump.jpg (70.1 KB)