Changing Firmware Update Policy from HMC to OS Managed on Power6

I have some smaller clients that managing firnware updates via i5/OS or IBM
i just makes sense. On my Power5 525 I can get into AMSI and cahnge the
policy to/from HMC/OS Managed. JUst tried to go a change a Power6 box
(E4A-8203) and it doesn't give me the option. It just simply states it is
set to HMC and that is that. While talking to a support tech about another
issue on aother box I asked him about this difference. He was able to to
pring on a pSeries guy that said my only option is to set the susyem back to
factory defaults adn then change it. OH! BTW that will blow away all you
LPAR cfgs etc and you will need to redo them.

Is this guy correct that on a Power6 I can't change how the firmware is
updated without all this hassle?