You can get the firmware you need from this site.. http://4pda.ru/forum/lofiversion/index.php?t586637.html Its in Russian but you can translate it no problem.I have used this firmware and can confirm it work OK with the CS818II. I had a similar problem with this box but I messed up the u-boot.bin file and the box looked completely dead - no hdmi or av output and no led activitiy on the the front of the box. I tried shorting pins on the flash to reset it but to no avail. In the end I had to use the debug port (UART) to load a recovery image. You will need a usb to serial ttl adapter if you need to got down this route. I got one from Aliexpress for under 2 euros. If you need more info I can provide details of how to perform the recovery