Same problem for me.... I'm back to 7.0.6 stable and bt is almost perfect... I use miband and hands free in my car, the big problem started with first 7.1 MIUI, I also try to change only the modem(baseband) but not working.. same problem...
With all MTK phone is simply... its't enough change the file called "modem..." in dir system/etc/firmware apply same permission than the original... if is compatible usually working
I hope working also with MIUI and 4g phone...
I have problem with multi device, I have mi band and when connect in my car is instable... Disconnect and connect continuosly random... sometime also miband don't connect and I must turn off and on BT... With old version working well..
When I have time try to upgrade and change only the...
Yes right in global there is only 4/5 language, for me the bluethoot problem started with 7.1 version, the baseband change, for now I went back at 7.0.6 eu and all working wery well.
I have also same problem ... with new rom the baseband is changed, in the car I have continue problem also with other headphone... for now I went back to 7.0.6 stable full wipe and the problem is gone...
Redmi note 2
Also K9mail is a very good app , and have a very nice plus respect native app, you can configure gmail and other (if the server can) in push, the mail arrive in a second and the drain of battery is less