If your mini 0806 camera are dead after upgrade, please follow the below to recover.

download here (http://www.mini0806.com/firmware/mini0806-DirectUSB.zip)

1, Extract the archive you have just downloaded,
2, Hold the UP button of mini 0806 and plug mini 0806 in to PC, it should make a sound to say new hardware plugged in, or an unknown device appears in device manager, (If it doesn't, unplug device and hold power button for 20 seconds till light goes out and plug back in) on windows 7 manually install the drivers, point to the folder you have just extracted, then go to DirectUSB/Drivers. if it doesn't work, please re-check the cable connection.
3, Let it install, then install the C++ distribution packs for your OS.
4, Run Direct USB
5, Click connect, make sure it detects device and says init dram ok.
6, Select relevant firmware file under firmware, then click Download, it should all go smoothly, this process is quite quick, as soon as it stops doing the flash it will show a full green bar and OK.
7, Unplug mini 0806, hold power till LED light goes off, then turn it on and it should boot up...

references:
https://forum.dashcamtalk.com/threads/everything-you-need-to-recover-mini-0803.6302/
https://dashcamtalk.com/forum/threads/bricked-0803-wont-start-help.6289