Note 8 sm-n9500 dual sim after android 9 update

[Mir_X]

Dear All,
I am currently using stock rom of samsung. after official update to android 9, I am currently facing extremely low in-call volume. During phone call, my buddy hears me clearly but for me, it is very difficult to hear him or her.

So that I am planing to use custom rom to solve this problem if there is no other easier way to get rid of it.
First do you have any advise for me to solve my incall problem after adroid 9 update ?
Second (if first step is not available ) which custom rom do you suggest me ?

My software version information is as follows :
Baseband version
N9500ZCU5DSH3
Kernel version
4.4.153-16246896
#2 Thu Aug 22 20:17:33 KST 2019
Build number
PPR1.180610.011.N9500ZHU5DSH2

 

[MAVERICK.T]

I had dirt clogging the earpiece, I used duct tape and it was back to normal

 

[Mir_X]

I had dirt clogging the earpiece, I used duct tape and it was back to normal

It must be really coincident that the problem in question has started after software update. I believe my problem is about software, not hardware.

 

[Mir_X]

It must be really coincident that the problem in question has started after the software update. I believe my problem is about software, not hardware.

Any advice for me ?