Okay so I've got an LG Optimus Fuel (L34C) that I've have for a few years now. It's slowed downed over the years, so I looked up ways to speed it up. I'd found all these articles saying that in 4.4, they'd introduced ART runtime, as opposed to the Dalvik runtime. I decided that I would give it a shot. I went into the dev options and changed the runtime to ART. A dialog box popped up saying that changing could cause instability and apps could misbehave. I hit OK and it went into the whole 'Optimizing app (x) of (y)' thing. That was on Friday, the 1st. It is now Sunday, the 3rd, and over the weekend, it has gone from 151 apps to 30, it has let me see the lock screen once, and trying to unlock it only took me back to the lock screen. It freezes while optimizing, and trying to boot it in safe mode doesn't work. This is the phone I've had since middle school, and since I don't currently have the money or the job to get a new one, I'd like to know if there's anything I could do to change the runtime back to Dalvik. It's not rooted.