@ajxpk This totally took me by surprise. You and I were just talking about these Jirachi multiboots in private last week I think, about my dream to make a GBA version Wishmaker. I had no idea we were so close. I'm even more overjoyed that we can now generate Negaiboshis too! I am curious though about the difference in appearance between this and the original Negaiboshi rom, as in, does it use this same generic master as BGF Zig, or rather something different. Considering this being one of the earliest events, I don't expect it to look like the 10ANNIV, etc.
This is probably the most enjoyment I've had since I dumped the 10ANNIV and Aurora rom. I think the stress of obtaining Aura Mew made it a less enjoyable experience, regardless of how happy I am to have it. Of course, us obtaining the remainder of the boxed 420 Mystery Mews was quite a unique and interesting experience.
I suppose we can't rebuild anything else for the time being without actual multiboot files. But that's basically impossible without possessing the actual roms (unless we can get our collector friends who could thoughtfully consider sharing the mbs, since they don't want to share the original roms). While hacking 10ANNIV/Aura MBs looks like it will be nearly impossible, it would be nice to theoretically recreate all it's variants that use the same algorithm/seeding, eg the 10ANNIV language variants, Doel Deoxys, etc.