Model Name: Zenfone Max Pro M1 ZB601KL
Firmware Version: PKQ1.WW_Phone-16.2017.2009.087-20200826
Rooted or not: Not at present
Frequency of Occurrence: All the time
APP Name & APP Version (If your issue relates to the app): Phone dialer, Camera, Sound recorder
About four days back, I started facing a strange problem where I have no sounds during phone calls. When I dial someone, there is no sound of the ring going through, and then when the other person picks up, again there is no sound heard either by me or the other person. This problem occurs even if I turn on the speaker, or attach wired earphones, or use bluetooth earphones.
Apart from this, I can take a still picture with the camera, but when I try to start video recording, it fails with the message "Could not start media recorder. Can't start video recording." If I try to record a sound with the Sound Recorder, it gives the message "Unable to start recording, please make sure that no other apps are using the microphone." As troubleshooting, I have checked and removed the microphone permission of all other apps apart from the Sound Recorder, but the problem persists
Previously, I had unlocked the bootloader and installed LineageOS 15 (Oreo) and had also rooted using Magisk. Some time back, I flash the stock ROM OREO using TWRP (after editing the updater-script file), then flashed the stock ROM Pie in TWRP, and after a little while, flashed LineageOS 16 Pie. If I remember correctly, I noticed the no sound during calls problem at this time. At this time, I could play a Youtube video / mp3 file with the audio working just fine, and I could record my voice with the Recorder app in LOS. Then I again flash Stock Pie, and then Stock Android 10 but the issue wouldn't go away. At this point, I also noticed that the Camera and Sound recorder were having problems as well (in stock). I then flashed LOS Oreo, and the Camera and Sound Recorder problem vanished, but the no sound during calls remained. I then wiped everything in TWRP, got rid of TWRP by flashing the stock recovery, then flashed the unedited stock Oreo using stock recovery, but the problem remained. I let it update on its own (FOTA) and it downloaded a lot of updates from Oreo to Pie, but the problem still remains. For some reason, it isn't showing the Android 10 version as an available update.
(1) No sound during phone calls, in stock and custom ROMs.
(2) Youtube and other audio files play fine, in stock and custom ROMs, both with phone speakers and earphones.
(3) Cannot record video using the camera, and cannot record audio using Sound Recorder in stock ROM, but this problem doesn't occur in custom ROMs.
At present, I am on stock Pie 087, with stock recovery, but the bootloader is unlocked. When in the stock recovery, I ran a root integrity check which showed 92 new files, 92 lost files, 1 modified file, and boot Normal and Advance check fail.
I have spent a large part of the last three days in trying to solve this problem. Please help, whether it is a solution, or just suggestions, or anything else even remotely connected with this issue which I could use to solve the problem.