Need help with 6610!

[taihv]

I have some nokia 6610, now they have strange problem! In Vietnam, we have 2 networks: Vinaphone and Mobifone. With Mobifone my phone haven't got any problem, but with Vinaphone when make a call i can't hear anything in speaker except keypad tone!!!!! Reflash, write PM file, change UEM... can't help. Have you got any idea?
B.G

[MobiFix]

try to change the software version may be it help

[taihv]

Can not sovle! I think change CPU can help me, have you got any other idea?
B.G

[MobiFix]

you have changed UEM and do every software steps and nothing solve the problem then you have to change UPP

[taihv]

Thanks for ur reply! I'll try and post result later!
Regard