extension_bootdev_hunt may have already run.
Without reboot we cannot make any assumption here.
Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
(cherry picked from commit d01720a8305a1e12b61bb40ff76c3a8a0d52d2f6)
[Resolved conflict: used ubman instead of u_boot_console per ci/master rename]