The newer (blue) dongle stores the original HD map inside in non-volitile ram. All you need is your laptop to put it back into your ECM (and the cables of course).
But if you have a TTS map the dealer cannot read it or work on it with the HD computer, but some dealers may have the TTS dongle and could read it. New ECM without the dongle that is married to the old ECM, so give the dongle with the bike if you sell it.
Problem is if you want to put the stock HD download back into your bike, and it's 2am and raining and you are a hundred miles from anywhere and just lost the whole left side of you bike (compensator and clutch for example).
TTS is a wonderful tuning device, version 3 is due out soon, and it will be even better, rumors have it tuning your spark maps automagically.
If I had a 7 yr warranty, I would only do the Harley tuner by a dealer, with a written assurance that it does not void my warranty. I have a two year extended warranty and will wait that long to do the engine mods.