Long story short.
1. Bought a Viofo A139 direct from Viofo.com. Unit was overheating on a hot day.
2. I asked Viofo to send me another unit, to see whether my unit was faulty or this was "normal".
3. Both units exhibited same behavior of overheating and corrupting last file upon shutdown (Not a SuperCap Issue).
4. Sent back the "Original Unit" and kept "Replacement"....Big Mistake.
5. Replacement ended up having a bad SuperCap, which meant when the camera shut down via hardwire kit, it corrupted the last file since Supercap didn't hold power to allow for a proper shutdown.
Ultimately, Viofo tried to give me an 80% refund and I refused. Then 85%..... Then a "Full Refund". Actually it ended up being about 95% because they claimed I was "refunded" on items before. Wasn't worth the headache or arguing. I sucked up the difference.
I ordered a replacement A139 3 Chan from amazon after getting refund. Will absolutely not subject this unit to direct sunlight. Apparently, heat doesn't play nice. Not sure if that killed SuperCap on the "replacement unit" or if unit just had a faulty supercap from the get go. Either way, things were resolved after a lot of "back and forth". But I found it overly insulting Viofo tried to give me 80 and then 85% of my money back on a product that went bad.
Viofo did email me and acknowledge I was right. That the SuperCap on the "replacement" unit had indeed failed per my suspicions.