Big Ag is a particularly odious repair troll, and John Deere is its standard-bearer. The company has been trying to felonize farmers' repairing their own tractors since at least 2015:
They told the US Copyright Office that farmers don't own their tractors - because tractor firmware is copyrighted, it is licensed, not sold, and farmers must abide by the company's license terms.
https://www.wired.com/2015/04/dmca-ownership-john-deere/
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