[OnePlus 8 Pro Questions & Answers] mxtuu222:
Hi,

I've recently upgraded my phone from version 11.0.4.4 to 11.0.5.5 and after upgrade all my modem configs were reverted to the default ones. I was not able to use VoLTE & VoWIFI as before.

Previous guides to run PDC tool didn't want to work on my unit, but after several hours, I've managed to solve how to do this. I'm sharing my method to all who has similar problems.

All the files for procedure are attached to the thread (use GUIDE ONEPLUS8 PDF) to see the procedure with screenshots. There is also guide how to root phone but it's not mandatory for VoLTE, VoWIFI change.

For POLAND PLAY VoLTE & VoWIFI choose DT_COMMERCIAL instead of PLAY_COMMERCIAL

VOLTE & VOWIFI – ACTIVATION & MODEM CHANGE

1. Enable USB debugging and have adb android shell installed

2. Upload to APK from tools folder to phone directory called Download

com.android.engineeringmode_V1.01.0.171117173719.25c8842-26_minAPI26(nodpi)_apkmirror.com.apk

com.oem.oemlogkit_1.0-1.apk

3. Find the apps and install

4. Type code on your phone *#800#

5. Don’t choose any app, stay in OnePlusLogKit

https://xdaforums.com/t/guide-magisk-for-oxygenos-11.4160833/

6. Go to Function Switch and enable (each time phone reboots)

a. VoLTE switch

b. VoWifi switch

c. VT switch

7. Go to your SIM Card in Settings and enable VoLTE and VoWIFI

8. Install QUD.WIN and QPST from the tools folder on Windows

9. Open CMD

# cd C:/adb

# adb reboot ftm

(this would turn off phone in development mode)

# adb shell

# setprop sys.usb.config diag,serial_cdev,rmnet,adb

(this enables diagnostic port needed for PDC)

10. Open Device Manager in Windows

11. Look for device IN20AA without driver – in the details find one with identifier MM_00 (there will be 3 same names but different identifiers)

12. Pick driver manually from file qqwan0.inf

13. Choose manually Qualcomm HS-USB WWAN adapter and adapt

14. There is gonna both devices visible in the Device Manager after few refreshes

a. Qualcomm HS-USB WWAN adapter

b. Qualcomm HS-USB WWAN adapter 9091

15. Try PDC with WWAN adapter 9091 if it’s working

16. If not, Unplug & plug the device (don’t write once more setprop, just plug it back)

17. In the Device Manager in Windows, delete Qualcomm HS-USB WWAN adapter but leave Qualcomm HS-USB WWAN adapter 9091

18. Open PDC once again and choose the only left Qualcomm HS-USB WWAN adapter 9091

19. The list of configs will be loaded

20. To change the modem config choose desired config ex. Commercial DT_POLAND (OLD ROW_COMMERCIAL NOT WORKING) – choose name, right click, select SUB0, SUB1 and click ACTIVATE. Check if in the row of your new modem config in SUB0 and SUB1 you have active setting

NOTE# For PLAY PL 260-06: DT Poland Commercial has VoLTE & VoWIFI

21. Close PDC. In cmd type command and reboot phone

# adb shell

Oneplus8$ reboot

NOTE!!! PDC MODEM SETTINGS MAY REVERT ONCE YOU TAKE THE SIM CARD OUT OF TRAY. YOU NEED TO MAKE THE CHANGE AGAIN TO DESIRED MODEM CONFIG.

#############################

CHANGE CARRIER POLICIES (UNLOCK BANDS)

Prerequisite is to have engineer apk installed.

1. Plug the phone into PC and dial *#801#

2. Turn on the Engineer Mode Toogle only

BASED ON: https://mt-tech.fi/en/modify-oneplus-7-pro-5g-8-and-8-pro-nr-lte-a-band-combos/

You have to install diag-driver manually if you have Android 11 installed. Check in Device Manager after enabled Engineer Toggle and connected USB to your computer you see two Unknown device labeled your phone model number. I have IN2013 (OnePlus 8 Europe).

Unknown devices in Device Manager

• Download Qualcomm diag-drivers and extract compressed zip-file.

• Right click the device and select Update driver.

• Select Browse my computer for drivers

• Select Let me pick from a list of available drivers on my computer.

• Select All devices.

• Browse drivers in extracted Qualcomm Drivers zip and find qmdm.inf

• Then find Qualcomm HS-USB MDM Diagnostics 90B6 and click Next to install it. You may get warning because hardware id doesn’t match. This driver still works fine.

• Now install same driver to second unknown devices (IN2013 if you have same model).

3. Now you should have driver installed to both interfaces.

4. Open QPST Configuration, Wait for Phone list in the window

5. Then go to Start Clients > QPST EFS EXPLORER

6. It will list all the QUALCOMM directories. Go to policyman directory

7. Copy the carrier_policy.xml (SIM1), carrier_policy.xml_Subscription01(SIM2) and lte_feature_restrictions

8. Modify files accordingly:

Modify OnePlus 7 Pro 5G, 8 and 8 Pro, 9 and 9 Pro NR/LTE-A band combos - MT-TECH.FI

On this instruction we will modify OnePlus 7 Pro 5G, 8 and 8 Pro band combo profiles with Qualcomm software. OnePlus has limited 5G access and 4G+/LTE+ Carrier Aggregation combinations and this instruction help you to unlock. However this instruction doesn’t unlock hardware defined combinations...

mt-tech.fi

or overwrite in QPST files with the modified files for PLMN 26066 with 5G and DSS enabled from folder on Onedrive called policyman (modified)

9. Reboot the phone

10. Dial in *#*#4636#*#*

11. Choose Phone

12. Choose Band config NR/LTE/TDSCDMA/GSM/WCDMA

Now it should work with all 5G bands regardless of some restrictions for not supported PLMNS