There could be many reasons why a camera may stop recording after 10-15 minutes, perhaps related to the power supply or the microSD card, or possibly an error in the settings since you have recently changed FW version. Here's a few things to check and eliminate before requesting a refund/replacement:
- Did you reformat the card in-camera? msetup doesn't support the beta firmwares, so i formatted through the phone
- Is the card full? Do you have loop recording turned on? the card is less than half full. loop recording is on
- Have you checked the card with h2testw? Can you try another card? i've tested it with dd writing 1GB and 2GB files
- Check the battery/capacitor is not loose inside i will but seriously doubt, i've opened it several times, everything looked fine (i'm using a capacitor)
- Check the power supply. Does the camera behave the same if powered from a phone charger? I'm going to connect it directly during next long drive to a new 12V power adapter I just got (Blitzwolf 2.4A) and see if there's any change