Default c18 mini pc for android

i bought this tv box and all it does is stay on a few minutes sometimes and reboots itself then loads up again ..reboots are random ..tried other power supply and tried other hdmi ports on tv ...is there some different firmware I could load on it to improve it ..other then the random reboots the device works perfectly.. this is the box I bought http://www.ebay.ca/itm/281316900362?...84.m1439.l2649 any help much appreciated thanks