“remove any thing that they might be able to do” is a hilariously broad brush to apply to three letter agencies in this day and age that were doing things like this 50 years ago.

I’m not saying it’s realistic that OP is being targeted for such surveillance. But if they are, good fucking luck! Flashing your firmware ain’t going to do shit when they’ve just gone ahead and replaced the chips on your board with their own that act exactly like a normal chip but have extra code that doesn’t get flashed when they don’t want it to.