Use the splitted boot-mirror as "normal" boot disk

[dark-sun]

Hello again,
I still make some disaster recovery tests,
I habe i splitted the root mirror, the splitted LV's automatically become the lvolb extention.
F.e. after failed kernel-patching, I have to use the splitted LV's (lvol1b, lvol2b, ...) as live-disks. But how can I bring this LV's in the system without the "b" extention?

Actuall I boot from the splitted disk into single-user-mode, but the / and /stand filesystems are already mounted. So I can't make:
# lvmerge /dev/vg00/lvol1 /dev/vg00/lvol1b
(lvol1 is "bad", lvol1b is the older, good version)

My idea now:
# Edit the /etc/fstab that /dev/lvolb will be used insted the "normal" lvol
# reboot
Than should lvmerge work (or?). Next steps:
# mv /dev/vg00/lvolb /dev/vg00/lvol
# reboot

But I think, there must be an easier (official) method to use a splitted boot-mirror after a boot-failure as "normal" boot-disk.

Regards,
Michael