How can I fix this MINIMAL BASH LIKE GRUB ERROR?

So, I just want to let you know that I made it to save my files, maybe if someone else has this problem, I would recommend to use an 64gb usb device for the testversion of endless, otherwise it’s a realy long process to save the files while running the testversion.

I’ve installed afterwards the whole endless programm and it works.

And now I’m more clever and saved my files on an external hard drive…

Thank you David for your help!