This is pretty serious. Someone just bricked his laptop by executing a rm -rf / command as root in Linux. As in destroyed. None of your usual BIOS/UEFI prompts appear and no hotkeys can help to restore the firmware.
The root (pardon the pun) of the problem appears to be traced to the mounting of /sys/firmware/efi/efivars as rw by systemd. systemd maintainer (Poettering) refuses to fix the issue.