Default error on restart

I flashed VT V6 on my F400K which changed the hardware and software to F400L and F400L100g respectively. Everything was working fine until I changed ART from Dalvik and now on rebooting it is giving me Unfortunately the process has stopped as well as process has stopped. I am not able to get past them.
I have backed up my stock image in recovery, can someone please advise how do I get into it and recover to original settings..
Please help

UPDATE: I am able to see my phone on device manager but dont see the PORT under properties (see attached), also once I press volume+ and plug USB, it starts booting and ends up with the error, not sure whether I am in download mode
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Current- LG G3 F400K
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