echo |format
0. c0t0d0 <DEFAULT cyl 3184 alt 2 hd 255 sec 63>
1. c0t1d0 <DEFAULT cyl 3184 alt 2 hd 255 sec 63>
でzpool status
syspool ONLINE 0 0 0
c0t0d0s0 ONLINE 0 0 0
みたいにゃ状況だとすると、prtvtoc /dev/dsk/c0t0d0s0 | fmthard -s - /dev/rdsk/c0t1d0s0
zpool attach -f syspool c0t0d0s0 c0t1d0s0
installgrub /boot/grub/stage1 /boot/grub/stage2 /dev/rdsk/c0t1d0s0
でいけるはず。fmthard: Partition 2 specifies the full disk and is not equal
full size of disk. The full disk capacity is
とか、Partition 0 of the disk has an incorrect offset
とか言われたら、formatのとこの作業が抜けてる気味。