GOOD NEWS I337 MF3 SIM unlock!
Just to be clear this may not be a permanent unlocking as I can't verify the results. (although I've had numerous times of restarting the phone and still good, but I am just repeating the developers words.)
All I know is that I have an i337 with the newly updated MF3 baseband, I tried everything and anything to get this guy unlocked since I am visiting overseas at the moment. I tried the 27663368378, the 0011, 9090 tricks and anything else you can think of, I even took it to one of the mobile service places and they were unable to even get an ack from the phone with it's new baseband. I tried downloading the "servicemode shortcut" from the play store and the only thing that app was able to tell me was that it only works with galaxy family (just as a reminder I have a galaxy s4!) I think whatever they had done, was even confusing the app, so it couldn't know its on a galaxy! anyways, after searching and searching I came across a link and conclusively an app called "RegionLock Away" by the chainfire group from the moment the app was installed it took 45 seconds for my phone to be unlocked up and registering to the network I am in right now.
As it's always been said, I don't take any responsibilities for anything that happens to your phone, as I believe they don't either, the only purpose for this thread was to inform some of the people like me that are willing to take the risk and enjoy the rewards or bear the pain if it succeeds or fails.
honestly, as I will myself when I get back in the states, consider donating to them or purchasing the app, since we need guys like these to save us in moments like these.
These are the links to the original posts
I know, that one is for note 3, but worked on my i337 MF3)
they are different follow them both and read them both.
I hope this helps somebody!