4XHD Jelly Bean  The Optimus 4X HD was a really well
built device with great 2012 specifications released in the
middle of last year. But it had some severe software problems,
and was locked down so tight nobody could do anything hackish to
try and fix them. Glaring software bugs and lack of third-party
support is a recipe for a dud in the Android community, and the
phone languished away with very few folks paying any attention
to it.  Today, all that changes. Jelly Bean has been leaked, the
bootloader has been unlocked, and there's already a ClockworkMod
recovery built and ready to go. I warn you -- it's not as
straight forward as some of the things you'll see, and you'll
want to read, read, and read some more before you get started.
Find all the information you need at the source link below. 
Source: XDA  There are 5 comments  pannonian says:  What do you
mean by "But it had some severe software problems"? Not severe
for sure. And it had numerous of firmware updates by now. Just
like other phones. It's one