Search warrants do not give the government the power to force you to write software, or an equivalent economic activity, against your will. There is no precedent for that in all of US history.
Well, that's partially because software is new. Again, I'm not going to claim it's legal now.
But "equivalent economic activity" seems a bit weak. A butler or security guard can be paid to open the door to visitors. So that's "economic activity", right? It doesn't mean they're not required to respond to a search warrant. And legal discovery can be very expensive.
Writing a simple software patch and recompiling doesn't seem all that hard. Rewriting the entire OS is a major undertaking. It may require passing new laws, but it seems unlikely that we'll end up with a bright-line rule where touching any line of code is forbidden. More likely it'll be a gray area where the line is drawn somewhere in the middle.
