I have been using version 3.1.11 on Huawei Ascend P1 and I am having this issue 80% of the time. When I answer a call caller can't hear me, I can hear them fine. They, or I have to hang up and when the caller calls again, usually after 10-20 seconds, everything works fine, we can hear each other. Also tried MIUI version 2.12.28, with same problem. Needless to say, it's driving me nuts. Tried going back to stock ROM and no problem ever. Anyone has any idea why this is happening? Thanks.