Not trying to rehash an old debate here. Also not planning on attempting anything based on the results as I plan to continue using my Baofeng. Just a theoretical question. I'm sure we can all agree that Ham operators are allowed to build there own equipment. For the sake of this theoretical question, we'll say that Baofengs are illegal for whatever reason. If a ham were to build there own radio, what's to say the source of the parts/how much is pre-built? My question is what/to what degree of modification is necessary to make a radio a home-built unit rather than manufactured. From what I understand, any modification technically invalidates the certifications. From what I gather, the major issue with the Baofengs is that they can transmit outside the Ham bands(not sure I've seen a 2m/70cm radio that couldn't do so without much programming changes). Would simply modifying the allowed TX frequencies in Chirp be enough or what level of hardware modification. In other words, what/where is the line betweeen "illegal" manufactured radio and homebuilt/legally modified(from ex commercial/ex-military) radios.