Download Android KitKat 4.4.2 stock firmware for Tronfy MXQ TV Box from here or from here. Download previous firmware from here. To flash firmware on Tronfy MXQ S805 Android TV Box via SD Card read this article.
Archive name: Tronfy MXQ 4.4.2 20150325 fw
Archive file size: 399 MB
Platform: AMLogic S805
Build number: m201-user 4.4.2 KOT49H 20150324 test-keys
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.