NFC is certainly one of the most useful, yet under-appreciated, features on many smartphones today. It finally seems to be catching on a little, and is included in such flagship smartphones as the Samsung Galaxy S III, HTC One X, Motorola Droid RAZR MAXX HD, and Nexus devices from the Nexus S to the Nexus 4. However, one thing that has always made NFC a bit less useful than it could potentially be is the fact that the screen needs to be on for a device to read NFC tags, a problem that is already annoying many LG Nexus 4 users.
This was such an annoyance that it eventually spawned a fix for the Galaxy Nexus, which allowed a NFC process to run in the background and the device to read NFC tags with the display off. Now, a similar tweak has been posted for the LG Nexus 4 on Android 4.2, and it looks to be usable even without root. The tweak is available in the form of a customized NFC .apk file, which must be installed manually in the /system/app directory. After pushing the .apk file to /system/app, the permissions need to be changed with the chmod 644 command, and then the Nexus 4 should be able to read NFC tags with the display off.
While certainly more convenient than turning on the display every time you need to read a tag, users should keep in mind that this could potentially pose a security threat if somehow a malicious NFC tag manages to come in contact with your device. However, the chances of this are quite slim, so once I finally get my Nexus 4, this will likely be one of the first mods that I apply. I can’t wait to set up my NFC stickers in my house and car, and automate much of my Android usage.[xda-developers]