Download latest Android KitKat 4.4.2 stock firmware for Tronfy MXIV TV Box from here or from here. To flash firmware on this box via SD card read this article.
You can download PC flash firmware from here.
Model: Tronfy MXIV TV Bo
Image file size: 819 MB
Platform: Amlogic S812
Update file name: MXIII Plus_202k4_16G_20150514_shumashidai / n200-ota-20150514.zip
Build number: n200-user 4.4.2 KOT49H 20150331 test-keys
By the way, you can buy Tronfy MXIV TV Box from www.tinydeal.com for only $119.99.
Caution: Please do not update firmware unless you know what you are doing, you really want it or it is absolutely necessary. Firmware updates may occasionally have bad results, like bricking your device, temporarily or permanently. The firmware update process is done entirely at your own risk. Before attempting to update the firmware, back up your data.