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Android Secret Codes don't work on Samsung SM-G531F.

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Android Central Question

I'm using a Samsung Galaxy Grand Duos set (SM- G531F). The mobile Network Type in this is EDGE- as a result even 4G SIM's provide 2G connectivity.
To correct this, i tried using the secret code *#*#4636#*#*. However, my phone does not respond this. Nothing happens (just waits for me to call as if this is a normal number). Does not work with Truecaller or any other App. Even 4636 on Phone INFO Samsung app fails to start the hidden menu.

I've come across the fact that changes need to be made in /EFS folder. Can someone please tell me what changes and how they are to be made? How do I get root access to this folder.

If there is any other solution to the hidden menu problem, other than going the EFS way, also please do let me know.


Well-known member
Jun 26, 2019
There's nothing you can do to change the bands that the device can handle. It's because of the hardware.