How can I change the 4G frequency my Galaxy S21 uses?

[Android Central Question]

I was given a Galaxy S21 whilst in Japan and I've tried to use it in the UK but it doesn't seem to work on LTE Band 20 which is the main 4G frequency used by my provider. Does anyone know if this is something that can be fixed by changing the software? Or is this a hardware issue?

 

[B. Diddy]

Welcome to Android Central! I don't believe that's possible, although maybe @mustang7757 can tell us if it's possible by flashing a different ROM.

Please register on this forum, which will allow you to engage in discussion more easily, as well as post images. https://forums.androidcentral.com/ask-question/409154-join-android-central-community.html

 

[LSuggers]

Thanks for your reply. I signed up after posting the question so I'm able to view replies easier

 

[mustang7757]

Hi , which model number you have , and is it snap dragon chip?

Maybe try this band selector from play store

https://forums.androidcentral.com/e...d=com.ray.samsungbandselection&token=DYGhHdjV

 

[LSuggers]

Model number is SM-G991. Not sure if it's snapdragon chip

 

[mustang7757]

Model number is SM-G991. Not sure if it's snapdragon chip

Is that SM-G9910?

 

[LSuggers]

This one https://www.gsmchoice.com/en/catalogue/samsung/galaxys21olympicedition/

 

[joeldf]

Is that SM-G9910?

It seems that either version has band 20. Or at least should.

 

[mustang7757]

It seems that either version has band 20. Or at least should.

Yeah

 

[mustang7757]

This one https://www.gsmchoice.com/en/catalogue/samsung/galaxys21olympicedition/

In settings>about phone model number?
I think u have snap dragon chip

 

[smvim]

I was given a Galaxy S21 whilst in Japan and I've tried to use it in the UK but it doesn't seem to work on LTE Band 20 which is the main 4G frequency used by my provider. Does anyone know if this is something that can be fixed by changing the software? Or is this a hardware issue?

Looking at which bands the Galaxy S21 includes support for, B20 does appear to be a missing in the S21 Asian variations:
https://www.kimovil.com/en/frequency-checker/JP/samsung-galaxy-s21
And yes, this is a hardware issue. The thing is ROMs are just software. It's the cellular radio chip the soldered into the logic board inside your phone that determines which frequency/bands your phone can support. Different carriers rely upon different cellular networks, and different phones can support only a specified number of those cellular networks. Each ROM is specific to each model of phone, and it only contains the necessary software, drivers, firmware, etc. that exactly correspond with the model of phone it's created for.
So it's a matter where that particular phone isn't going to support B20 no matter what software is involved.

(..... and as a side note, flashing ROMs that don't match a phone's exact model is generally a bad idea. ROMs are not interchangeable. If you do opt to intentionally flash a mismatched ROM if you're lucky the phone will boot up normally but the odds are really good some or a lot of apps and basic services won't work or will be quirky; if you're just kinda/sorta lucky the phone will be soft-bricked and be stuck in a boot loop, and you can just re-flash with the correct ROM to restore it back into working condition; if you're not lucky it'll be hard-bricked and it's time to just look forward with a new phone.)