It has been a few weeks since Lollipop rolled out to the LG G3 on AT&T and Sprint, but T-Mobile users have been left in the lurch. The update is finally available, but it’s not available as an OTA just yet. If you want Android 5.0.1 right now, you need to install LG’s (awful) update software on your computer.
After installing the device management tool. go ahead and plug in your phone and make sure USB debugging is on. LG’s software should detect your phone and offer to install a USB driver if the connection can’t be made. The update should pop right up and give you the option of downloading and flashing.
Just like a regular OTA, you need to be stock for this update to work. It shouldn’t delete anything, but back up important stuff just to be safe.