Google Nexus 4 — Dalvik to ART

Are you running stock 4.4.2, or a custom rom? I'm asking because if you're on 4.4, or sometimes 4.4.1, the Google apps in the rom are incompatible with ART which will cause a bootloop. Also, if you're rom is deodexed it can cause this too. There are reports that after converting to ART the first boot can take over an hour on the N4 too.

Sorry I've taken a while to answer Jose, busy weekend. Being a nexus it should be pretty easy to resolve. I'm presuming you're running a total stock setup (unrooted, locked bootloader, stock recovery) so if you want to remain this way you'll probably need to flash the stock firmware, details on how to do this are on xda here. This will wipe all user data though, but it is fairly straightforward. If you haven't used adb or fastboot before then google it, but it's basically similar to a virtual linux machine on windows and the commands you'll use are simple. If you want to unlock the bootloader to flash a custom recovery then it'll save a lot of time, but you'll still lose your data when you unlock the bootloader the first time. Information on how to do it is here, again on xda. Before you do anything read the thread and ensure you understand the basics, have adb/fastboot set up (easy) and have any relevant files (recovery, rom/firmware) on your PC. If you need further help feel free to post or message me as the processes for the Nexus 4 and Nexus 5 are very similar.