Hmmmm. Sounds like users digging for Apple to release a SMC update for the 5,1 that could be applied to all the 4,1's out there. Considering there's never been an update to the unique dual SMC in the 4,1/5,1 platform, perhaps there is a physical / hardware design issue that prevents both SMC's from being updated?
It's not a problem with the Renesas/Hitachi micro-controler, the internal ROM is updatable - can't be dumped but can be updated.