[PeterisP]

Intent makes all the difference in the eyes of law.

If a jury of your peers decides that you configured that firmware to protect your data from thieves, then it is not a problem.

But if a jury of your peers doesn't buy your assertion of that, and instead becomes convinced that you applied that (otherwise reasonable and legitimate) feature with the intent to destroy evidence of a crime so that it doesn't reach the court, then setting it up was a felony.