Comment 7 for bug 1692175

from the changelog of grub-pc ... 3.10:

2017-05-19 - Mathieu Trudel-Lapierre <email address hidden> grub2 (2.02~beta2-36ubuntu3.10) xenial; urgency=medium * debian/patches/install_signed.patch: don't install fb$arch.efi; it breaks "removable" installs where files are all installed to /EFI/BOOT; and it also doesn't belong in the /EFI/ubuntu path for the default case. Fallback install simply needs more work and isn't ready for SRU. (LP: #1684341) * debian/postinst.in: clean up fb$arch.efi.

(source: https://ubuntu.pkgs.org/16.04/ubuntu-proposed-main-i386/grub-pc_2.02~beta2-36ubuntu3.10_i386.deb.html)