How? Can you please send a screenshot of the diagnostic tool where it's showing that the bike was derestricted in the past?
I'm taking my Bosch training in a week, so I should know better then. But I was talking with one of the other mechanics at the shop I work at and he's done his training. We were discussing it and when I asked him about it he said that the Bosch systems logs certain parameters which tells them if a bike has been derestricted.
So while I don't have first hand knowledge how its done, I should know better in about two weeks.