Create mobile youtube copy and load in box, dont know you need keyboard & mice or not or remote enough to operate then you can download offline.
Actually offline download not much flexible. Box come with 8 GB memory & out of that 4 GB Android firmware take. Remain 4 GB, you need to maintain minimum 2 GB memory to load new firmware.
Dont want advice you to move china box. lt non dth budget box come with 2 / 4 GB RAM around 2000 to 3000. l avoid and moved to airtel. Mentally not happy but from heart very happy even remote & charger made in chin which l unaware that time.