Probably there are very few ppl outside of the Garmin programmers who are capable of modding fw as has been done by or for that RU seller. It's a lot of work to do for no return, so it probably won't be offered 'free' if someone else does succeed doing it. You could see how difficult it is yourself, compare the 3 firmwares v3.10, 3.20 & 3.70 and try to find in them what's disabled the Astro receiving US frequencies when used in such places as EU in v3.20> and/or what's enabled the pairing of TT5 and TT15 in V3.70. Whoever did the fw mod and also effectively protected it from copying deserves what he gets out of it, purely in a financial sense of reward for work performed. That is totally ignoring the legal, moral and ethical factors of course.