[Q] No sound when calling (ring and voice) topic

Hi guys,

I have a Canadian sgh-i337 (Bell) and when I call someone I cannot hear the ring, the other person and that person cannot hear me. The call is connecting and all. This problem started when I flashed a Rom of the GT-i9505. I am on the new bootloader (MK6).

What I have tried or checked:
- Battery pull;
- Clear cache/Factory Reset;
- In call volume;
- Headphones (same problem);
- Speaker (same problem);
- Flash most recent modem (MK6);
- Odin stock Bell firmware;
- Check if receiver is working with *#0*# (It is working perfectly)

The problem happens for 90% of call I make or receive. For the other 10% the problem occurs after 1-2 minutes of talking.

Weird thing is when I flash the MK6 modem or Odin stock Bell rom it is working for about 10 minutes and it starts doing the same thing.

Been trying to find the problem for 1 week... I read alot before posting here and a small amount of people on other forums have the same problem but no fix for now...

I am thinking that it is an hardware problem but I don't have another phone so I want to try anything before return it to samsung for repair.

Your help is very appreciated,

Nicolas