[Cialug] LVM weirdness

[L. V. Lammert]

Upgrading the drives in one of our boxes, .. swapping them out went fine
until the last one - when it was swapped, the LVM broke. Not a problem, I
was planning on rebuilding that md as plain RAID6 anyway, ..

BUT two of the six drive partitions in the array show "Unused LVM PV", and
it cannot be changed or removed. Tried:

 * Setting the partition type to Linux RAID;
 * Copying the MBR from another drive
 * Setting the LVM flag OFF with parted

 * pvremove:
	# pvremove /dev/sda4 -f
	  WARNING: wrong checksum 3ed414e in mda header on /dev/sda4 at 1
	  WARNING: wrong magic number in mda header on /dev/sda4 at 1
	  WARNING: wrong version 0 in mda header on /dev/sda4 at 1

Can't find any other hints online, .. anyone have a suggestion on
clearing the PV flag?

	Thanks!