I can't wait any longer - and in the case i made it worse i accepted the risk with the thought to come running back crying 
For similiar problems:
It's not enough to change UUID to the new one in /etc/fstab and to generate a new grub.cfg with sudo update-grub you have to reinstall grub - at least it helps me.
So first backup your /boot/efi, than remove the old bootloader sudo rm -r /boot/efi/EFI/ubuntu, now sudo grub-install /dev/sda (it notice EFI enabled, your drive can have another name). After than you regenerate grub.cfg with sudo update-grub2 and reboot praying that you don't made it worse. 