Here is the newest stock firmware for Neo X8 and X8-H quad core tv box. Note, it just the beta firmware.
1.) Enabled NFS protocol;
2.) Fixed “App Market” problem of MINIX Metro launcher;
3.) Enabled support for Logitech HID devices;
4.) Added PS3 game controller support;
5.) Improved eMMC read/write performance;
You can get download the img file here.
Here is the instruction for how to flash the firmware
and thanks to bob finless, if you have problem to flash as the above instruction,you can use the sd card to flash, HERE IS THE ZIP firmware download link