Hello everyone, I'm stuck with a problem I cannot find a valid solutions.

Problem: while updating && upgrading, notebook (Mac) went in power management and display turned off. When back, as usual, i thought it would just a matter of dropping in the username and pwd (was logged with root), but...didn't worked. Tried to reboot many times, I always see the boot menu, i can choose Live USB with Persistence and Encryption, then I can put the decryption pass and i can see the dragon logo, but after that, a black screen with a flickering mouse pointers that alternates its blink with the cursor on top left corner of the screen. Definitely, the interrupted updated have broke something.

What I did: tried various combination of keys to enter a rescue mode (never had to previously) and reach a shell. Also, I tried to reboot with Persistence but without encryptions and updated && upgrade from there, nothing changed.

What I suspect: i could see once in my tries, there was an error message with the bfmac on the black screen, but it never appeared again. I could also, when rebooted with grub, see that he seems to not be able to install drivers that are not free. But if I setup up wifi, it works.

I'd like to ask for some help. I cannot loose that USB as I worked too much to set everything up in it and I am still studying a lot. What would you do? Please start from the black screen, step by step...

Infinite thank you.