Extract the Metroid NES ROM from Metroid Prime
This is an Android app that will extract a copy of the NES version of Metroid using the "NESemu.rel" or "NESemuP.rel" file from your legitimate backup copy of Metroid Prime.
Currently, this will only extract the NES Metroid ROM using the USA version of Metroid Prime, and will not extract the FDS version of Metroid. The "NESemu.rel" file must be pre-extracted from the ISO using Dolphin, Gamecube ISO Tool, or similar tools.
Disclaimers
This app utilizes Metroid decryption code written by FIX94: https://gist.github.com/FIX94/7593640c5cee6c37e3b23e7fcf8fe5b7
The existence of this app does not imply support of piracy by any means, and should only be used with legitimate backup copies of Metroid Prime.