Import or Add Biss/Powervu Keys in Freesat GTMEDIA GTC ANDROID SET TOP BOX, GTMEDIA GTC DVB-T2/S2/C ISDB-T S905D Sample Key File : https://goo.gl/vaP7dE (it is not updated with latest keys but you will get an idea about formats)

GTMEDIA GTC ANDROID TV BOXBISS KEYPOWERVU KEYFREESAT GTC BOX BISS/POWERVU KEY METHODGTMEDIA GTC DVB-T2/S2/C ISDB-T S905D