Although there’s no reports about the availability of Jelly Bean update for T-Mobile Galaxy Note (SGH-T879), but Android 4.1.1 is now available and ready to be installed on this phone, even though not the official firmware from Samsung. We must realize that this phone is less popular since T-Mobile has taken out the phone too quickly and according to rumors it will replaced with Galaxy Note 2, so there’s only few people who have this smartphone.
Additionally, it affects the custom ROM development, fortunately there are developers who are willing to give their time to build a custom ROM for us, hoping you’ll be more pleased to use this android phone. Before planning to install/flash a custom ROMs/firmwares you should install a custom recovery using Odin, you can follow a guide to flash a custom recovery and root on Galaxy Note T879. Here is a custom ROM crafted specifically for our device:
Jelly Bean ParanoidAndroid 2.12 by JamieD81.
This custom ROM is based on CyanogenMod (CM10) with Paranoidandroid experience, this firmware provides choices for you to use Tablet/Phablet UI that makes your device look more attractive and beautiful, I’m sure you’ll take out your decision to sell or trade this device . Since this JB ROM is still in development stage and it has several bugs, you might encounter couple of force closes, but rest assured there will be a fix for it someday.
The Dev suggest you to utilize TWRP recovery to flash, for the download link and more information you can check out the original thread.