I've just stomped this: https://www.reddit.com/r/pokemonrng/comments/5ny1el/scripts_and_guide_to_help_automate_rnging_a_shiny/
It's a program that helps in making a legit savegame that has a shiny jirachi checksum, which is kind of cool. Maybe it's time to just upload all possible shiny jirachis from the bonus disk? It would certainly be a lot easier, and since they are limited...
EDIT: I think the 9 only(?) possible shiny jirachis are already here (and they've been for a long time): https://sites.google.com/site/kaphotics/resources
Seed: 0x353d, PID: 0xba7df435, Nature: Bashful,