[Samsung Galaxy Note 9 Guides, News, & Discussion] laneyyy:
I followed a guide by XDA User applepay from this link, but just wanted to try and simplify it because i found it pretty complicated to understand at first.

It would be worth reading that thread before this even if it doesn't make sense. Please also read this complete thread before you attempt it.

I have only followed the guide so i can't answer any questions to help. I am not responsible for any problems you run into. This is just a guide of what I did to get mine to work.

I was successful using my SM-N960F going from CSC XME to TEL.

I cannot confirm that this method will work on other models, but i don't see why not considering the guide was originally for a S9.

Make sure you select your exact model when downloading files and flashing files. Using other model firmware may brick your phone.

Backup your files! I used Smart Switch on windows. This method will wipe your phone in the process.

Use the original usb cable you got in the box and install the Samsung USB drivers if you haven't already.

I have confirmed on my device that OTA updates work fine after this procedure.

Please comment if you think there is a better way or there is an error in this guide.

Download your combination file from here

Download your new CSC firmware from here

Download Samsung Odin 3.13.1 from here

Download RealTerm from here

1.	Open Odin.

Click AP and select your combination file.

Put your Note 9 into download mode by turning it off completely, then holding the volume down and bixby buttons while inserting the usb cable. Confirm that you want to enter download mode.

Click start in Odin.

Once this is complete, your phone should boot into the combination firmware and show your model number. Close Odin.

2.	Open RealTerm and go to Port tab.

Set Baud to 230400 and Select Port to ssudmdm0000 or very similar name.

Click the change button.

Go to Send tab.

Enter "AT" and click Send ASCII.

If you get a response like

"+USB READY

BOOTING COMPLETED

AT"

or

"AT"

or

"OK"

or

"BOOTING COMPLETED

AT"

Proceed to the next number.

If you didn't get a response click +CR and send again.

If you get a response like "ERROR" proceed to the next number.

Still if you didn't get a response check your phone status and cable status.

If everything is normal proceed to the next number.

If still you didn't get a response it means your phone or cable is not normal status.

3. Enter "AT+PRECONFG=1,0" and click Send ASCII.

You will get this response.

AT+PRECONFIG=1,0+PRECONFG:1,???

OK

-??? is your current CSC.-

4. Enter "AT+PRECONFG=2,???" and click Send ASCII.

Enter ??? you want to change to another CSC.

You will get this response.

AT+PRECONFG=2,???+PRECONFG:2,OK

OK

-??? is your changed CSC.-

5. Enter "AT+PRECONFG=1,0" and click Send ASCII.

You will get this response.

AT+PRECONFIG=1,0+PRECONFG:1,???

OK

-??? is your changed, current CSC.-

6. CSC change is now complete. You can now close RealTerm.

7.	Open Odin again.

Turn your phone off and then put it into download mode again by holding the volume down and Bixby buttons, then plugging the usb cable in.

Fill each field (BL, AP, CP and CSC) with their respective files from the firmware which has the new CSC.

Use the CSC file in the CSC field, not HOME_CSC.

Click start. This will now wipe your phone completely.

8.	Your phone should boot into android and everything should be complete!

Enjoy using VoLTE, VoWiFi and RCS!