Yes its truly noteworthy project. They exploited Canon cameras by first managing to blink red charging LED. Then they used the LED blinks to transmit the firmware out. Then they built custom firmware which boots right from SD (thus no posibility to break the camera). The Magic Lantern firmware for example allows many basic cameras to do RAW 4K video recording (with unlimited length) - feature which is not even in the high-end models. But it has much more features to tinker with.
Watch a lotta NorthridgeFix youtube channel. He is excellent and leads you through his thought processes. Also get tons of hand ons experiences. Disassemble everyday things and try to figure out how they work / how to modify them. Remote controlls, routes, childrens toys, mobile phones.