Originally Posted by paperwastage

Samsung, it's a hidden band selection mode or unlocking all bands: Some providers lock it out, but you can flash some stuff to unlock it. So far, it's still available and not locked out entirely.

https://xdaforums.com/t/how-to-enabl...mwave.4554611/


This feature on Android "backup calling" is ymmv, may not work reliable for android (Samsung/pixel).

Pixel: https://www.reddit.com/r/GooglePixel...nd_android_14/.

Samsung: may not work in usa. May not work if the data-enabled sim is roaming. https://r2.community.samsung.com/t5/.../td-p/11194437