He has added an interesting disclaimer "Please note: I am in no way saying that you can, should, or are allowed to fly with a card updated in this way (even though the bits in it are identical). I am not claiming that I plan to or am flying with such a card. All experimentation was performed on a card and a GPS that is not used for IFR flight."

Also author appears to have commented on this thread with a similar disclaimer. Very neat hack, but yea, walking a very fine line with the relevant aviation authority :(