Enabling dual sim on my S21.

[Mysocalledella]

Hello guys, please I need help. I have an S21 Korean version with dual nano sim support but only one sim is active. I need to know if changing my csc will help activate the dual sim functionality, thanks 🙏🏾 

[johnz237]

Hi! Welcome to the Samsung Members community!

It's not recommended to "change your CSC"; phones are supposed to be used in their intended regions. The only way to change the CSC is through rooting methods, which has too many risks to discuss on the forums, as we're not able to.

*Changing the CSC on your Korean S21 with dual nano-SIM support is unlikely to activate the dual SIM functionality if it's not already enabled.

[arianwen27]

Quick answer is don't attempt it.

Long answer is dual sim is a hardware and software feature. There's a chance a software flash can enable it, or it can error and break your device. Changing scs and device firmware should never be attempted. Different region phones are all slightly different in hardware. Flashing other region firmware might be incompatible or break it.

Flashing different firmware can also void warranty (though you won't have one by now) and cause other strange behaviour in your device. It could even trigger the knox anti tamper bit. We cannot endorce you try it or explain how to.

While it has a possibility of working, it can also brick your phone and break all sorts of things

[JAMES4578]

Hi @Mysocalledella Welcome to the Samsung community, not advisable to change the csc as mentioned.
Having an out of region device can effect the dual sim functionality, in connections-Sim Manager-More Sim Settings is Dual Sim Always on selected and does resetting Network connections make no difference? If you go to Settings-connections-Mobile Networks-Access point Names is an APN listed for the inactive sim?

[Mysocalledella]

Okay thanks for the response 

[Mysocalledella]

Okay, well noted!

[Mysocalledella]

There's no dual sim option in the sim manager, but in the sim slot there's two contact pins for two sim cards. Meaning the hardware supports it.

[Tourbillon De La Vie]

It doesn't support dual or esim. Never did

[JAMES4578]

The uk version does offer dual sim support unlike the Korean one. https://www.samsung.com/uk/support/mobile-devices/how-do-i-install-a-sim-card-in-my-galaxy-s21/

[Tourbillon De La Vie]

Yes, but not the Korean version that's subject here