[Samsung Galaxy S20 FE Questions & Answers] Esormit88:
Forewarning: I cannot guarantee this will work for everyone or that your data will not be wiped. Backup, backup, backup! This resulted in NO WIPE for me. All data was intact.

I just spent a long time trying to figure out why I cannot get the October updates on my Unlocked S20FE that is currently on T-Mobile. No matter what I did, I couldn't get it to give me an update option. I heard swapping SIMs with a non-TMo provider will do it, but I didn't have access to one.

This led me to learning about Samsung's CSC system. CSC is "Consumer Software Configuration" or "Country Specific Codes". These codes are locked in to the phone until a new SIM on a different carrier is inserted. I tried many network reset options with no luck. You have to force a reset of the CSC.

First, the initial CSC for my USA unlocked S20 FE 5G is XAA, which just tells the phone it's an Unlocked US model. You can see your CSC codes under Settings > About Phone > Software Information > Service provider SW ver. Look at the third line and see 3 codes like such "XXX/XXX/XXX". My understanding is Samsung saves a history of CSC codes: 1) The current 2) the previous and 3) the original. It can move back and forth between the first 2, but the will never resort back to the 3rd (original CSC) even if you remove the SIM. Before, I saw TMB/TMB/XAA. TMB is the T-Mobile CSC, and XAA is my original. So I needed to somehow overwrite the TMB codes to XAA.

How to:

1. Remove SIM and keep it out until the end.

2. Go to Settings > About Phone. Long press the 15-digit number next to IMEI to Copy it, or write it down.

3. Open Samsung Phone app, type *#272*(IMEI NUMBER)# <Paste your IMEI without the (), and Dial. You won't be able to dial this with a SIM in.

4. You will see a list of codes in a "preconfig" window with your 2 codes at the top. For Unlocked XAA models like myself, select XAA, (if you have a different original CSC, then use it). There are sites with lists of available CSC codes if you wanted to do different carriers/regions.

5. Click Install, and then select Sales & Network Code Change, (Network change only changes the 2nd CSC, you must select Sales & Network to change both 1st and 2nd CSCs), click Ok. and your phone will reboot. Once up, go back to Software Information, check the CSC codes are set to XAA/XAA/XAA, then you should be able to check for your software update.

6. Update Software, reboot, then insert SIM, and reboot again and you will be up to date and back on your network.

Essentially, you're just setting the phone as if no SIM card was ever inserted. Had you performed an update on a brand new phone over wi-fi before ever inserting your SIM, you would have the update the exact same way. After I got the update over Wi-Fi and my phone reset, I reinserted my SIM and my CSC codes are set back to TMB/TMB/XAA with the baseband version of G781U1UEU1ATJ5 and the October 1, 2020 Security Patch. Should this happen again where T-Mobile's updates are lacking behind, a simple CSC reset would do the trick again.

Good luck. Let me know how it works for you. Again, I'm not responsible for you messing anything up or losing data, but it worked perfectly for me. This could be used to change regions and carriers on your phone as well, not just for updates.

EDIT: I haven't been able to get back into the "preconfig" CSC change screen anymore. I've read that others have only been after to get back into the preconfig change screen after a factory reset. So it sounds like you can only modify the CSC once between factory resets.

EDIT 2: Of course, the day after I do this, T-Mobile finally pushes the update. I'll leave this information up for future usage.

EDIT 3 (07 Dec 20): Thanks to info from dopeyone2011, the dial code *#*#27262826#*# works to change CSC update multiple times after the original one. As of 07 Dec, I was still on the 01 Oct security patch on T-Mobile. December's isn't available, but I was able to get the 01 Nov patch. Hopefully T-MO gets their act together so this doesn't have to happen monthly.