Samsung’s flagship handsets have had FM radio support for years but the chips were usually locked down which meant that they couldn’t be used to access local radio stations. Samsung had confirmed not too long ago that it would partner with NextRadio to enable the functionality and while it works just fine on carrier-branded units, those who own an unlocked Galaxy S9 or Galaxy S9+ in the United States are unable to use the FM radio feature. It has now been confirmed that the unlocked variants will soon receive support for this feature as well.
Many would have expected the FM radio feature to be usable in the unlocked variants as well given that it works just fine on the carrier-branded variants. That’s not the case, though, and you can use it right now on an unlocked device.
It turns out that a software issue in the unlocked variant is preventing the handsets from the accessing the FM radio chip. Until it’s resolved, users won’t be able to listen to FM radio using their smartphones. The issue is due to the fact that Samsung mistakenly didn’t add the NAB FM API to unlocked devices. The model numbers that currently do not work for FM are SM-G960UI and SM-G965UI.
They may not have to wait for long, though, because NextRadio has confirmed that a firmware update will be released soon that’s going to fix this issue.
Source : http://www.ubergizmo.com/2018/03/unlocked-galaxy-s9-and-galaxy-s9-fm-radio-enabled-soon/