Some good and useful Xiaomi Yi hacks. (1.2.x firmware)

enable RAW

t app test debug_dump 14

Also you need convert it to DNG and do some corrections URL to software. Don't use with timelapse - RAW files to big for this.

better JPEG

100% quality?
writeb 0xC0BC205B 0x64

(be careful, could be not for 1.2.x fw)

t ia2 -ae exp 100 0 0

(be careful, shutter speed could be too long)

t ia2 -ae exp 400 0 0

better video

writeb 0xC06CE446 0x02
writew 0xC05C1006 0x420C

WDR and some other PRO-like magick

t ia2 -adj ev 0 0 120 0 0 130 0
t ia2 -adj l_expo 163
t ia2 -adj autoknee 255
t ia2 -adj gamma 220
t cal -sc 14

disable noise reduction

t ia2 -adj tidx -1 0 -1