Part of original post from "Firmware"
"Hello.
Firstly i want to say, that device very well, but not perfect. 1st - it's hot device. That give us problem with overheating and freezes on recordings with 1-2-3-5 minutes pauses. But this can be easily corrected by the correct installation (By the way, my friend was forced to attach the radiator and fan from the battery side) on NC700 in the luggage compartment on the battery side."
I had nothing to do, because I have this problem only with long trains at an ambient temperature of 25 degrees Celsius (1, 2 pic). My friend replaced the radiator and made holes in the main body (3, 4 pic).
1

2

3

4 (left - original, right - custom)

Trunk is hot place at NC700 while weather is warm.
Not sure if this could help, but turning the screensaver = OFF and Screendisplay OFF = 3mn it also helps to keep the unit cool on warm days.
Could not believe you can do something like that on the DVR!!
Smart and skillful!