Misdreavus

I found my checksum in HxD hex editor at line 2FF0. It's EDED (pic). I'm sure this is it because I claimed a Jirachi whose seed is EDED. My target Jirachi has a seed of F500. I changed EDED to 00F5, then loaded my game in PKHeX. I used the "Verify Checksums" option, and it outputted the following to the clipboard: Block 00 @ 02000 invalid. That block contains the value C8 (pic). What should I change this to so that my checksum is valid? I've looked for guides on hex editing, but haven't come up with anything for Ruby/Sapphire.

Thanks for your reply. What programs did you use for hex editing and checksum regeneration? Also, would you mind explaining to me (or pointing me to the proper resources) how it changes?

I was told that it was possible to edit the checksum in a Ruby or Sapphire save file using a save editor to cause the Colosseum Bonus Disc to give me a shiny Jirachi (or any other Jirachi of my choice out of the possible 65536). Is this something that can be done with PKHex? I opened up a save file with it and I don't see an option to edit the checksum (only an option to verify it). Also, the same source told me that I may need to edit other variables so that my checksum remains valid, or else the disc will catch that I have an invalid checksum and won't give me the Jirachi. What would I need to edit? I've attempted to RNG this Jirachi with no luck, so I've used rschecksum before. Do I need to edit my information in PkHex so that it matches whatever info in rschecksum which causes the output seed to be the seed of the desired Jirachi? Is this my checksum? rschecksum also uses several other variables (starter, Pokémon encountered, time in game, clock setting game options) in computing my output seed, so I'm not sure how I would account for these in a save editor. Any and all help is appreciated! EDIT: Alternatively, what I may do is play through until I get the Pokédex and Running Shoes, save once at a predetermined point using EonTimer (leaving the other save bank blank) and backup my save. When viewing my save in a save editor, I'd like to know how far off I am, so how can I simply view the checksum so that I can see how long I should open the game before I save again? When I do save again, I can then view my checksum again and see if it's what I want it to be. If it is, I get the Jirachi. If it's not, I restore the save file from my initial backup, and try again.