There seems to be various sources on the Internet on how this can be achieved. A Modem Flashing version that required a rooted phone and a code dialed on the phone.
Can someone tell me which of these two are valid?
Android Enthusiasts Stack Exchange is a question and answer site for enthusiasts and power users of the Android operating system. It only takes a minute to sign up.Sign up to join this community
You need both pieces. The LTE radio was disabled, in software, by the 2.0.1700.48 radio firmware update. In order to enable LTE, you'll need to downgrade to an older radio image (2.0.1700.33 or earlier), then use the
*#*#4636#*#* dialer code menu to enable LTE. If you try to use the dialer code on the .48 or higher radios, it will not work.
If you're comfortable with unofficial images, there are also "hybrid" radios that you can use instead of downgrading below the .48 one. These basically attempt to integrate the updates present in the later radio images, while maintaining the "bug" that allows LTE to be enabled. They are made by third-parties and not endorsed or supported by Google/LG.
There is an XDA thread that compiles a list of all official Nexus 4 radios, along with downloads to each version. If you want to enable LTE, you need to do the following:
fastboot flash radio /path/to/radio.img
*#*#4636#*#*. This will bring up a new menu.
There is also an app on Google Play that attempts to streamline this process. It requires root, and I cannot personally endorse it because I have never used it. Based on the reviews, it appears to generally work well on Jelly Bean (or earlier), but may have trouble on Lollipop.
Also be aware that the N4's LTE chip only supports one LTE band, AWS band 4. If your carrier has deployed LTE in your area on a different band, then you won't be able to use it.