- Download the firmware, the file should be update.zip. For BFS 4KH, I could get it @ http://pan.baidu.com/s/1kTrCcMr (password: xpef). It includes YouTube and Google Play, but not the Rainbow launcher, nor XBMC, but these can be side-loaded.
- Now copy update.zip on the root of a USB flash drive formatted with FAT32, and at least 1GB free storage.
- Connect the USB flash to the USB 2.0 port of the device, as the USB 3.0 port can’t be used for firmware upgrade.
- In the current firmware, go to Settings->System->Local Update, and select the drive letter for the USB drive (e.g. D), and you should be prompted with a window asking you want to go ahead with the upgrade.
- The box will then reboot, show the usual Android upgrade animation, and reboot automatically in the new firmware.
Overall the procedure is very similar what is done on Amlogic devices.
Now the test firmware I received did not include XBMC, nor the necessary codec. So I installed XBMC for HiSilicon (password: amaw) and MXPlayerCodec (works with BFS 4KH only), and I could run XBMC, and downmixed audio worked with AC3, and some other Dolby and DTS codec.