using jmr2 way to install grub which is saner

using jmr2 way to install grub which is saner

01:46 < jmr2> Glanzmann: thanks for your various documents. I just tether-booted the whole chain for the first time, and it's quite fun to watch.
01:46 < jmr2> Two comments: 1) instead of deleting fbaa64.efi (I still have it without ill effects), you can uninstall grub-efi-arm64-signed and its dependencies.
01:47 < jmr2> 2) I couldn't get dpkg-reconfigure grub-efi-arm64 to install grub. I ended up using mps's --efi-directory instead of your --removable, since it uses a path instead of a device - less risky.
01:47 < jmr2> In the end, installing grub is three commands: apt-get install grub-efi grub-efi-arm64-signed- ; grub-install --target=arm64-efi --efi-directory=/boot/efi --removable ; update-grub