The first sale doctrine might save them.

If I buy your patented thing from you, that exhausts your patent rights for that copy of the thing. If I modify it, and do something you don’t like with it, you can’t come after me under patent law.

Note that I didn’t say anything about contract or copyright law—they may have signed something saying they wouldn’t reverse engineer the chip, or the sale could come with an end user Eula to that effect.