Okay guys, here is what I tried, and works perfectly!
Unmirror my rootvg
Reduce my rootvg (remove hdisk1 from rootvg)
alt_diskinstall -C hdisk1 (this takes a mksysb of hdisk0, and restores it to hdisk1, and change the bootlist to hdisk1, and sets bootimage on hdisk1)
Reboot (will automatically...