You could try using adb to change the device back to Dalvik. However, you will need to have had USB Debugging enabled. If you can't do the below, a factory reset may be your only option.
Android Debug Bridge (ADB)
A prgram made by Google for Programmers and developers. Its based on command line and basically communicates with your Android to respond to certain commands.
Setting up ADB
Java Runtime environment or Java Development kit
Your Device Drivers
An Android Device
USB Debugging MUST be turned ON in the device for ADB to see it.
If you are having trouble completing Pre-Requisites, there are several guides featuring them.
First Download Android SDK.
There may be any compressed zip file or exe file
If zip file, then extract it to C:\android-sdk
If exe file then double click on it and install it in C:\ Drive(or any other drive you want)
Now to get adb and other tools, you need to download 'Platform Tools'
To download them, go to the android-sdk folder and double click on SDK Manager
It will ask you which package to download? However, it is your choice which package to Download, but here, we will only talk about platform
Tools. So, simply tick on Platform Tools and click on install. Once you have done it. Go to the platform-tools folder in the directory where you installed android-sdk. You will find several files there like adb, fastboot, aapt, etc
Now, you can backup the whole folder of android-sdk to any external storage that will make you not download package
again if you want to. You can have it placed in any computer and run it as it does not require registry to work
Now, you are just one step away from using adb. Next step is SKIPPING SETTING ENVIRONMENT VARIABLE (If you however want to set environment variables. Click on Show Content)
You can easily append the sdk platform-tools and tools folder to your systems environmental path variable directly from command line(cmd) by simply issuing one command and performing a system reboot:
SETX PATH "%PATH%;SDK_Install_Path\platform-tools;SDK_Install_Path\android-sdk-windows\tools" -m
Just replace the "SDK_Install_Path" in the above with the proper path of your SDK installation. Example: C:\android-sdk-windows
Type cmd in the search bar. Copy cmd.exe from there. Go to the directory where you have installed android-sdk. Go to platform-tools folder. Paste cmd there, right click on it and in the settings, select Run as Administrator.
To change back to Dalvik:
adb shell 'echo libdvm.so >/data/property/persist.sys.dalvik.vm.lib'