HI , there ,, i have front cam. upgraded to V1.9xx fine,, but rear cam. fw is a 1 file .rar ?? i thought it should be .bin file ,, so i converted it ,, but either type file does not upgrade,, the sd card was formatted to FAT32. The camera is V1.8xxx and is a V1 rear cam. when i look at viofo video it shows 2 files . ?? Any ideas. thks