Default SBF from 4.4 sprint rom to 4.2.2 RW stock

Ok i am well aware that some things will not work on my phone, but would like to test some things and possibly see about getting 4.4 working on my Republic Wireless phone. My question is if i flash a Rom can i just SBF back using the RW.sbf file? Also yes i unlocked my Bootloader using the $43 method. So i don't think there should be an issue. Some have mentioned that there was a Bootloader change and that you can't Downgrade...can anyone Confirm this or have a link to the info? Thanks Guys