If needed you can wipe and clean install and then restore from a Time Machine backup from before you installed the update. Just remember the day you installed it.
erm... no! The SMC is not some kind of software component sleeping on your HDD. It's a ROM-like part of the hardware. The process can't be reversed by doing a restore from a backup. Same for the EFI. And also a SMC reset or PRAM reset won't help you with it... If you do the update, you're stuck for the moment.
I've seen more of these kind of comments recently, and I'm somewhat concerned that the most out there don't really know what they're doing.
Be careful if you do such updates! And make sure you have the Mac the update was made for! I also already saw some guys trying these updates on 13" and 15" Macbook Pros with SSD installed... guess what happened... nice brick! *facepalm*
That's due to the fact, that these updates are not ment for the public and there are no checks built in them, which would prohibit the flashing process of the SMC. So be extra careful!
But the good news is: works like a charm on my 11" 2010 MBA