Force 3G mode on dual-SIM Android One phones I want to forcibly enable 3G mode on a dual-SIM Micromax Canvas A1 (Android One) running Android 5.1 Lollipop.

I've already searched the net for answers, but all I came up with was using *#*#4636#*#* which unfortunately is disabled by the manufacturer.

So what else can I do to force 3G?
So it's a dual SIM phone. Only one SIM can be set to use in 3G mode and the other in 2G. It is your wish which one uses 3G. Common method is to open Settings / More networks / Mobile networks / Network mode (for Sim1 or 2) / WCDMA only.