[userbinator]

We’re not sure exactly what the technicians did to remove the chip – heat gun, maybe? – but it came off cleanly and you wouldn’t notice it was missing unless you were specifically looking for it on the board.

Almost certainly, or more precisely, a "hot air rework station". For someone with experience, it only takes a few minutes to remove and replace BGAs with one.

[eigenloss]

As far as hardware hacking goes, this is tremendously unimpressive work. They didn't even check for PCB antennas, which would have been trivial.

It would probably take six months, minimum, of real work to actually airgap a Macbook (with any level of confidence in its security).

[monochromatic]

And on top of that, it’s just about the only way it can be done non-destructively.

[dfox]

Another (and for large-ish BGAs actually better) way is IR rework station.

[brianpan]

I disagree. Hold my beer...