Contents of /mnt/etc/fstab:

devfs   /dev    devfs   rw      0   0
ptyfs   /dev/pts ptyfs   rw 0 0
fdescfs /dev/fd fdescfs rw 0 0

----

$ kenv vfs.root.mountfrom=zfs:zpool0/ROOT/sys
$ reboot -r

[...shutting down services...]

Trying to mount root from zfs:zpool0/ROOT/sys
No suitable dump device was found
Setting hostuuid 447d...
Setting hostid: 0xd5...
Starting file system checks:
Mounting local filesystems:mount: /dev/pts: No such file or directory
mount: fdescfs: Invalid fstype: Invalid argument
Mounting /etc/fstab failed, will retry after root mount hold release
mount: /dev/pts: No such file or directory
mount: fdescfs: Invalid fstype: Invalid argument
.
Mounting /etc/fstab filesystems failed, startup aborted
ERROR: ABORTIGN BOOT (sending SIGTERM to parent)!
2025-06-... asus-p5qd-turbo-rescue init 1 - - /bin/sh on /etc/rc terminated abnormally, going to single user mode
Enter full pathname of shell or RETURN for /bin/sh: