One wrong code won’t brick your phone, but a factory reset code will wipe your data instantly. Have a working code we missed? Test it on your S9 and drop it in the comments (but warn others if it’s dangerous).
How to boot Galaxy S9 into Recovery Mode | ADB commands for Samsung | Unlocking hidden LTE bands
If you own a Samsung Galaxy S9 or S9+ , you might have heard whispers about “secret codes” that unlock hidden menus, test hardware, or pull up diagnostic data. These codes—entered into the stock Phone dialer—can give you insider access to your device’s inner workings.