Bug#776676: Possible recurrence

[Markus Vuorio]

Dear maintainer,

It seems that the same symptoms are currently occurring in my system.
I'm running buster with OpenZFS 2.0.3 from buster-backports, and have
upgraded my root pool with the latest features.
My /boot is not on ZFS.
Update to grub-efi-amd64 2.02+dfsg1-20+deb10u4 rendered my system
unbootable and indeed the issue seems to be missing pool name in the
generated kernel command line.

I can work around the issue by hard-coding the correct pool name
instead of using this grub-probe line in /etc/grub.d/10_linux :
rpool=`${grub_probe} --device ${GRUB_DEVICE} --target=fs_label
2>/dev/null || true`

-- 
Br,
Markus Vuorio