Just want to report that I managed to power the old Silver Sunhans with this Xiaomi 10000mah 5V2A powerbank AND a usb step up cable DC-DC 5V > 12V cable. I flew the bird and both led light green and blue just as normal. My only question is, does it have to be 12V2A? Because converting from 5V2.1A to 12V means I'm only getting about 800mA. Which I took the risk and it worked for now. Not sure if undercurrenting it will have any downside to the booster in the long term.