Yesterday, 2/7/19, I received a factory unlocked Note 9 (512GB version) that I ordered from Amazon. We already had T-Mobile on my wife's Note 5 so I had ordered a sim for the Note 9 from T-Mobile, installed the sim in the Note 9 and it seemed to work fine. This morning the phone prompted for an "Android Software Update" which I allowed. Subsequent to the update, the speaker for listening to phone calls is barely audible. Sounds and volume are configured correctly according to Samsung support so it seems the speaker functionality was lost by the software update (no apps have been installed since I received the phone). Samsung support wants me to take the phone to a "UbreakIfix" location for repair. This seems pointless as the phone does not have a hardware issue. Even if "UbreakIfix" reinstalls the factory software, the same issue will recur when the phone does its first "Android Software Update". Any helpful suggestions appreciated.
To know for sure if it is software or hardware I suggest you first try starting up the phone in "Safe Mode" and see if it happens in there. If it doesn't, then it is likely something on the device and not the update. Even if you didn't install anything, something preinstalled on the phone could be the culprit.
Now if it happens in "Safe Mode" as well, then you can try doing a "Hard Reset" yourself to restore it to the status it was when you got it to see if that will resolve it. Should even that not resolve it, then it is likely hardware and just the timing of when it occurred made it seem like software.
To get into "Safe Mode" please do the following.
1. First turn off the phone.
2. Next press and hold "Power" until you see the manufacturers logo on the screen, then release the power button.
3. "Quickly" press "Volume Down" and hold it for few seconds until you see the message "Safe mode: ON" or something similar.
4. If you wanted disable it, simply repeat the steps above, and you should see "Safe Mode: OFF" rather than on.
For the "Hard Reset"...
NOTE: Doing this will clear 'all' the data on your phone, so it is suggested you not choose this option unless you have to, or aren't worried about losing anything on the device.
Be sure you back up any data you want to keep, to a computer or cloud account, before doing the reset.
To "Hard Reset" the phone...
1. Make sure that the phone is actually powered off.
2. Remove your SD card, if there is one in the device.
3. Press the "Power" and the "Volume Up" buttons, together, until you see the start-up logo on the screen.
4. Once you can see the logo, release the buttons and allow the device to enter the "System Recovery Mode".
5. Next use "Volume Down" button to get to the "wipe data/factory reset" option.
6. When in recovery mode the "Volume Up" and "Volume Down" buttons are how to can navigate and highlight what option you need.
7. Once you have selected the "wipe data/factory reset", press the "Power" button to select that option.
8. On the following screen, repeatedly press the "Volume Down" button until the "Yes - delete all user data" option is what is selected.
9. Then press the "Power" button to hard reset the phone.
10. If you took your SD card out in step 2, when the device is up and running again, reinsert the SD card.