Comment 9 for bug 1891718

And regression tested on an NVMe (but non-nvme-subsys) device on an ARM server:

ubuntu@d05-4:~$ mount | grep /boot/efi
/dev/nvme0n1p1 on /boot/efi type vfat (rw,relatime,fmask=0022,dmask=0022,codepage=437,iocharset=iso8859-1,shortname=mixed,errors=remount-ro)
ubuntu@d05-4:~$ ls -l /dev/nvme0n1p1
brw-rw---- 1 root disk 259, 1 Nov 3 23:40 /dev/nvme0n1p1
ubuntu@d05-4:~$ readlink /sys/dev/block/259\:1
../../devices/pci000d:30/000d:30:00.0/000d:31:00.0/nvme/nvme0/nvme0n1/nvme0n1p1
ubuntu@d05-4:~$ sudo grub-install
Installing for arm64-efi platform.
Installation finished. No error reported.
ubuntu@d05-4:~$ sudo apt install libefivar1 libefiboot1
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following packages will be upgraded:
  libefiboot1 libefivar1
2 upgraded, 0 newly installed, 0 to remove and 60 not upgraded.
Need to get 78.2 kB of archives.
After this operation, 8192 B of additional disk space will be used.
Get:1 http://ports.ubuntu.com/ubuntu-ports focal-proposed/main arm64 libefivar1 arm64 37-2ubuntu2.1 [42.5 kB]
Get:2 http://ports.ubuntu.com/ubuntu-ports focal-proposed/main arm64 libefiboot1 arm64 37-2ubuntu2.1 [35.7 kB]
Fetched 78.2 kB in 0s (233 kB/s)
(Reading database ... 77021 files and directories currently installed.)
Preparing to unpack .../libefivar1_37-2ubuntu2.1_arm64.deb ...
Unpacking libefivar1:arm64 (37-2ubuntu2.1) over (37-2ubuntu2) ...
Preparing to unpack .../libefiboot1_37-2ubuntu2.1_arm64.deb ...
Unpacking libefiboot1:arm64 (37-2ubuntu2.1) over (37-2ubuntu2) ...
Setting up libefivar1:arm64 (37-2ubuntu2.1) ...
Setting up libefiboot1:arm64 (37-2ubuntu2.1) ...
Processing triggers for libc-bin (2.31-0ubuntu9.1) ...
ubuntu@d05-4:~$ sudo grub-install
Installing for arm64-efi platform.
Installation finished. No error reported.