Hi there blacki,
Ok i will tell you a little story:
There is a Smart car with a 1000cc engine that can do 0-100 km/h in 13 sec.
There is a Ferrari car with a 4000cc engine that can do 0-100 km/h in 3.1 sec.
Can a smart car do a 0-100 Km/h in 3.1 sec?
NO, but we can modify it so it can do! OK! we modify it and we run 0-100 again, and you get 0-100 km/h in 8 sec! WOW nice improvement.
BUT you cannot EVER get 3.1 sec with a smart car if you DON'T change the WHOLE car (engine,transmittion etc or buy a Ferrari).
So your Xiaomi Yi (and mine too) can go at 2K with the engine(Ambarella A7LS Processor, Sony Exmor R BSI CMOS 16 mp sensor).
You can modify to get better quality with a fast card (35mbits/s or 50mbits/s) BUT you will never get 4K like a GoPro does.
So you can do these:
1. Remove all components inside the Yi camera and place in there the GoPro engine(cpu,sensor etc). If you do that, post it here, im so interested to see that.
2. Sell Xiaomi Yi ( i can buy yours for 20 USD
) and then go buy a GoPro 4 Black edition at 500USD.
Hope you got the point now...
I'm sorry guys(not you blacki, all the other guys from the forum).