“Hacking” electronic toys isn’t homogeneous, as attested by these two examples, taken from (1) Game Boy Modding (a boo about to modify GameBoys) by Greg Farrell, (2) A fanzine by T.A.C.O. Team about toys hacking.
While the formats of the two documents are close (using drawings and informal ways of describing things), there is a clear different between the level of precision in the first book, and the second, which is clearly more playful (“take the wire and touch ANY part of a circuit board”). Perhaps this is caused by the purpose of the first book, which is more about maintaining/fixing the device, and less about fucking around with it.