I'm not new with linux nor debian and usually I can work my way around myself, as long as I'm the source of the problem.
I installed debian sid through a netinst (64b amd64, the computer is B50-10), checked the usb stick image integrity, it was fine, then went along with the installation, choosing LVM for partitioning, then MATE for desktop.
Rebooted, and it could only (try to) boot though PXE when the cable was on, or reboot endlessly if it was off.
I can't even access the BIOS, the PXE menu is almost immediate, what the heck with that for god's sake ?! I never met a computer like this.
It has seemingly mandatory "EFI": couldn't assign the "label" in the partitioning menu to any partition, nor could remove it from the EFI partition which was the first on the disk after a 1 Mo empty one. Very nice





I had debian on this computer before, and I never had that PXE stuff going on, which is a nonsense.
The only hypothese I can bring on, is that the installation program messed up with that EFI partition in a way it shouldn't have ?
Now how do I access the BIOS ?
In the meantime I'm trying Mint, but being based on debian, there's a chance it will end up the same.
Thanks for your help.