osprober complaining about ZFS is a known issue. I don’t know if I bothered to file a bug report, so this will probably be the report for that.
Side question: where did you find an installer image with ZFS support? I tried the daily yesterday but I had no ZFS option. ** Changed in: zfs-linux (Ubuntu) Status: New => Confirmed ** Summary changed: - Error during update ZFS installation and during update-grub + osprober prints errors about ZFS partitions -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to zfs-linux in Ubuntu. https://bugs.launchpad.net/bugs/1847632 Title: osprober prints errors about ZFS partitions Status in zfs-linux package in Ubuntu: Confirmed Bug description: It is probably a minor problem. I did run an upgrade of my official ZFS installation in a VM. It did produce an error: device-mapper: reload ioctl on osprober-linux-sdb6 failed: Device or resource busy Command failed. I have a dual boot so afterwards I did boot from ext4 and did run update-grub and that did report the same error. See attachment, first lines the update-grub and the lines afterwards the last part of the zfs apt upgrade. I could boot the systems afterwards and Linux 5.3.0-17 were loaded. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/zfs-linux/+bug/1847632/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp