[Linux] Boot loop after new installation (on Toshiba Portege Z30-a)

UEFI boot stuff is some what sad story. It is said that M$ does not stick to its standard and "BIOS" manufacturers quite often prefere to do this entreprise's bidding. This can lead to problems with non-Windows OS to boot. See also https://en.wikipedia.org/wiki/Unified_Extensible_Firmware_Interface#Criticism. If I remember correctly, Windows overwrites fall back files in EFI/Boot eventhough it has its own directory as all OS are requested to use.
I have run into a problem related to this when Debian Stretch made a system upgrade. A fresh install of it or (l)ubuntu did not remedy.

Symptom

After a system installation or a system upgrade grub does not get loaded. After the manufacturer splash screen a message beginning with "System BootOrder not found." appears for a second or two and the computer reboots.

Cause

The wrong file is at EFI/Boot/bootx64.efi

Solution

Copy EFI/<your operating system>/grubx64.efi to afore mentioned lockation like

sudo mount /dev/sda1 /mnt
sudo cp /mnt/EFI/ubuntu/grubx64.efi /mnt/EFI/Boot/bootx64.efi