Those wishing to install a later version of grub2 can use a debian installer. This procedure creates a "net" install of Debian to a partition and then installs grub-2.06 to the /boot of that partition. you can then relocate the EFI dir and then repurpose the partition for whatever your needs. You should have on hand a second way to boot your machine other than from the disk you wish to install grub-2.06 to.
1. go to
https://cdimage.debian.org/debian-cd/cu ... 64/iso-cd/
and download
https://cdimage.debian.org/debian-cd/cu ... etinst.iso
2. this minimal iso can be burned to a cd (or written to a spare USB should you prefer).
3. Boot the installer and choose custom install then direct the installer to install Debian to an unused partition on the disk you want to have grub-2.06 on. You do not have to wipe the disk, but you should save or move anything you wish to keep in the selected partition.
4. reboot with a puppy (or your preferred OS) from a working install. Ths can be from the disk you just installed Debian to, but if you do not get the following instructions correct on the first try, this is where you need a second way to boot from a different disk if your machine will not boot on the first try.
5. in the case of wanting to replace your existing UEFI bootloader with gru2.06, find the current bootloader EFI dirs and files, (typically located on the first FAT32 partition of your disk) and move all into a tempory folder that you can delete later after your new configs are working.
6. copy /EFI out of /boot in your new Debian install to your preferred boot partition. move grub.cfg also and add any grub stanzas from your exisiting grub.cfg in the temporary folder.