I have used this phone since its launch, and I am quite disappointed with its firmware.
Firstly, the phone got very hot sometimes. An update fixed this problem but phone still gets hot now and then.
3rd party camera apps displayed blank camera. I had to stick with default camera. Sometimes, 3rd party camera apps can work mysteriously. But the problem still happens now and then as well.
After some firmware updates to fix the "getting hot" problem, I got new problem. Phone battery drained out like crazy. I almost wanted to give up.
Then 2 weeks later (such a long time for fixing this serious battery issue), another update finally fixed it. But it brought another new problem. Sometimes, when I put the phone in the pocket, it auto rejected phone calls or auto sent message such as "I will call you back". I had to use lock screen PIN/pattern to prevent this.
During national day, I recorded the airplan show at Marina Barrage. I started recording and the time was counting, then I stopped recording, the video wasn't saved! I was super angry. Tried recording a few times but unsuccessful, then next day, somehow it was working again. I decided to let it go asap and use back my spare iPhone.
I will not go back to Xiaomi anytime soon. All I need is quality control of the firmware. Not some frequent ******** updates which bring new problems all the time. Dual 4G sim support, 5" 1080p screen, decent battery, all these nice features will not compensate for shitty firmware the Mi 4i has.
* Forgot to mention that the cellular data sometimes didn't work, I'm not sure it was because of the signal or because of the phone. Haizz.
And every time I update, the change log shows "Change log is not ready yet. Please wait for a sec." Seriously? Wait for a sec??? After a week, it still shows the same. Hilarious.