After ufs to zfs conversion.

Rebooting with command: boot
Boot device: disk File and args: 

detached mirror

Can't mount root

The file just loaded does not appear to be executable.

To boot the system from the ok prompt this worked for me:

{3} ok boot /pci@9,600000/SUNW,qlc@2/fp@0,0/disk@1,0 -Z rpool/ROOT/Solaris10ZFS

Check the bootfs setting on the zpool

# zpool get all rpool
rpool size 136G -
rpool capacity 59% -
rpool altroot - default
rpool health ONLINE -
rpool guid 14558664169034125133 -
rpool version 32 default
rpool bootfs - default <============== no bootfs specified.
rpool delegation on default
rpool autoreplace off default
rpool cachefile - default
rpool failmode continue local
rpool listsnapshots on default
rpool autoexpand off default
rpool free 55.5G -
rpool allocated 80.5G -
rpool readonly off -

To fix the issue:

zpool set bootfs=rpool/ROOT/Solaris10ZFS

Reattach the mirror:

# zpool attach rpool c1t0d0s0 c1t1d0s0

In order to boot from either disk (in the event one of the disks fail)

At the ok prompt > setenv boot-device zfsdisk1 disk0
In OS > eeprom boot-device=zfsdisk1,disk0