Sorry, but I have a learning remote, so I never needed a code for my Roku.
A few things to keep in mind:
1> Remote codes vary according to remote brand.
2> Go to your remote manufacturer's web site to find remote codes.
3> If your remote is older than the device you want to control, there probably is no code for your device.
4> If you have a Roku "gaming remote" (Roku 2XS or Roku 3) it is not an infrared remote - you will not be able to use any other remote except a Roku remote.
5> Invest in a good LEARNING universal remote. Unless your device is controlled by Bluetooth or RF, you can learn any commands from the original remote.
I've had my learning remote for five years now, it cost me under $30, controls 7 devices, and the only thing it won't control is My Roku 2 XS and my ceiling fan (it's controlled by RF, and not many universal remotes support RF.)