Are there any save editors that has the ability to edit Event Flags like editing the chosen starter Pokemon, edit Legendary Pokemon whether it is captured or not etc...
Unsetting flag 825 will show the sprite, along with fixing constant 155 for the event trigger. Can confirm it works for both Ruby and Sapphire.
I also just tested the above Regi flags, and they work for Emerald as well. Rayquaza at 773 works for RS only.
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Other legend/static battle flags I'll try to document are:
RS: Island Lati, possibly the roaming Lati
Emerald: Rayquaza, Island Lati, possibly roaming Lati, Mew, Deoxys, Ho-oh, Lugia, Sudowoodo
FRLG: Articuno,