So, thanks to timmy10shoes (one of my Bionic mentors), we have a new method for people to use to get to JB. All of you (including myself) who rushed to upgrade are going to kick your own @$$ now.

Trust me. Using the cdt.bin from the 246 FXZ and using it to replace the cdt.bin from the 98.72.22 FXZ, you can then use the House of Bionic's FXZ Keep Data option to upgrade to JB. Big deal, says you...I'm already upgraded....so what....Ah the skeptics. The big deal, says I.....say you don't like JB or can't live without root. Fine....put the 246 FXZ back into the House of Bionic and downgrade away.

"WAIT, WHAT??!! I heard, FROM YOU, that I'd brick my phone doing that!" Yes, YOU will...cause YOU took the update and didn't use this process. Therefore your security is updated. Using THIS method, however, the security is NOT updated and you can happily downgrade to your heart's content.
I take NO responsibility for those that try this. This is a USE AT YOUR OWN RISK and I will not provide ANY support for it whatsoever. But it has been confirmed to work so long as you follow the quite simple directions EXACTLY.
A word of warning...those who took the JB update already, don't bother. You're screwed. You WILL brick.