I have problem when i want to upgrade my Zenithink c91. I already copy the image from zenithink and placed it into root folder of my sdcard. reset the device and press camera and power button. Android System Recovery running but there are erorrs "Bad BootLoader Arguments "(null)" unknown volume for path /udisk/factory_update_param.aml cant mount /udisk/factory_update_param.aml anyone know how to solve this problem? Thanks. Sharing is Caring!