[Samsung Galaxy Z Fold3] srikanth.addala:
As the title suggests, I was able to successfully change the CSC on my factory unlocked (unbranded) Fold 3 - F926B/DS bought in Germany with OXM firmware having Android 13 & one UI 5.0 from EUX to INU csc using SamFW Tool v3.31 in hardly 2-3 mins. Kindly note that I also looked into other options to do this like Samkey tool (paid service) and alliance shield app (which doesn't work anymore) etc before engaging with the SamFW Tool as none were simple/working with no complications whatsoever involved.

My main objective to change the CSC was to enable call recording and couple of other features (including some pleasant surprises listed in the end of the post) which were available in the INU csc with little to no hassle. The process was pretty simple, straight forward and most importantly, FREE ;). It DOESN'T require any factory reset, flashing of roms or wiping cache partition before or after the process.

The step by step guide process which worked for me is as follows:

STEP 1: Click here - SamFW Tool Download - to download the latest version of SamFW tool.

STEP 2: Remove the sim card and connect your phone to a computer and make sure the phone's drivers are installed.

STEP 3: Unzip the downloaded file. Right click on the file SamFwFRPTool.exe and 'Run as Administrator'.

STEP 4: After the software opens, make sure your phone is detected before proceeding. If its detected, click on ADB tab in the software.

STEP 5: In your phone, go to developer options and enable 'usb debugging'.

STEP 6: In your phone, open phone dialer and type *#0*# to get into test mode. Leave the phone unlocked and keep it aside now.

STEP 7: Click on 'Change CSC' button in the ADB tab of the tool. Now the tool will connect to your phone, check and list the available CSCs which your phone model supports as shown in the pic attached.

STEP 8: Choose a CSC which you wish to change to from the drop down menu in the pop-up window as shown in the pic attached.

NOTE: The tool also has the option to force the phone to accept a CSC not listed/supported as well by manually entering the same. However, I would not recommend doing it if you really wish to get OTA updates and also to evade any unforeseen issues. I must admit, I haven't frankly tried this and do not know what lies in the pandora box to be honest.

STEP 9: After choosing the CSC from the drop down, the tool quickly connects to the phone, changes the CSC and restarts the phone.

STEP 10: After the phone restarts, unlock the phone using your pin/password, insert your simcard, check the change of CSC in software information, disconnect the phone from the computer and also disable the 'usb debugging' in the developer options.

That's it! All done. Phone restarts with the new chosen CSC and the related features will now be active!

BONUS: There is also an option in the ADB tab in the SamFW Tool named 'Battery information' which gives the complete information of the battery status including the 'charge/discharge cycles' along with its temperature, voltage etc. like in the pic attached. Do note that the information shown in the 'Genuine battery' section isn't correct for some reason and always shows as 'NO' for any phone with/without genuine battery.

With my choice of INU csc the following major changes/surprises were noticed over the EUX:

1. Call recording and a couple of other INU specific features are now enabled (google for more info on what csc enables what features).

2. Not sure why but Battery backup has increased significantly after the csc change to INU. SOT (Screen On Time) which has fallen to 3-4 hrs after the OTA update to One Ui 5.0 & Android 13 is now back to 5-7hrs or more.

3. RAM management has definitely got better. With EUX csc it used be around 5-6GB during standby and now its always around 3-4GB when the phone is idle.

4. Instead of 4G or 4G+, now it shows LTE and LTE+.

5. Mobile data speed has increased both in 5G (Jio True5G network) and in LTE+ when compared to EUX CSC.

6. 5G signal strength has improved drastically. Signal loss or switching to 4G+/LTE+ is very low now.

7. 5G to 4G/LTE switching while calls (VoLTE/VoNR) is more seamless now. Latching back onto 5G network after a call is a breeze now unlike earlier with EUX csc.

8. Phone definitely got faster for some reason. Can very much feel the difference when switching between apps, multi-tasking, even opening/closing apps and other day-to-day tasks.

etc...

Haven't tested whether the OTA updates will still get pushed after the change in CSC yet, as my phone is already updated to the latest patch as I write this. Should absolutely work IMO as long as we choose a CSC which the phone supports but in any case will update the thread once the next update via OTA is available/pushed by Samsung.

Disclaimer: Please be informed that all the above information is purely based on experience of using the tool for changing CSC only which worked well for me with my Fold 3. Cannot take responsibility if it doesn't work for you.

EDIT 01-NOV-23:

Tried changing CSC using the latest SamFw Tool v4.7.1 today on my Fold 4 | 512GB | Native csc EVR and was successful in changing it to INS csc in the very first attempt without any hassles whatsoever.

P.S ~ Used a Win 10 Pro PC with Kaspersky Premium AV. Do note that Windows Defender throws an error while installation of the tool alerting that this software might harm your computer. Just click on 'more info' and then on 'Run anyway'. All is good after. Just to be sure, scanned the whole system after the activity and also the related files. All are clean of any viruses.