New Miui7 : 3g Don't Working

[Karukera80]

This is a long time that i have this problem. This is the same as MIUI6 :

http://xiaomi.eu/community/threads/miui-6-mobile-network-state-disconnected.27203/#post-242662

http://xiaomi.eu/community/threads/3g-problem-miuiv6-on-mi2.26413/