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iFixit Tears Down McDonald's McFlurry Machine, Petitions Government for Right to Hack Them
(www.404media.co)
This is a most excellent place for technology news and articles.
Earliest I've heard was from MIT and the pranks they do. I think that was from the fifties.
Yes, Ikea hacks are much later. Me and my wife were doing it/calling it that around 2005 when we modded a desk. It was intended to be an example of the dual usage of the word hack.