So RNG Reporter is outdated? Alright, I'll try the new one.
About the nature, just tested it and pokesav doesn't change it, even if it changes the PID. It just makes the pokemon illegal (sometimes legal too, not the case of Jirachi). It must take the nature into account when it generates a new PID.
About the IVs and the nature of the Jirachi, I just put them in Pokefinder and got this result:
If I change the PID and SID to this one, would it check out? EDIT: Ok, just found out it has to specifically say "Channel" lol, because I read that CHANNEL Jirachis were generated with the Reverse Method 1 I thought it was the right one.
Well!! I did it!! My Jirachi checked out just now! I came to the conclusion that I did edit the HP IV, as it was a 31. When I searched for a docile CHANNEL Jirachi that had all the original IVs except the HP, there was only 1 result!! This must be it... after 15 years, not only did the Jirachi appear, but it has been restored to its original self! Don't know when the SID may have been modified or corrupted, but if one of you said that it's impossible to have a CHANNEL Jirachi with that SID, it must be true.
Thank you each and every one of you! I couldn't have done it without you! My icey Jirachi says THANK YOU too, for rescuing it!