For my save file,
6F66951C, 6F669A35, and 6F6696CF is the nat dex number of the Legendary Pokemon saved for the Max Lair
and changing these from bool2 to bool1 lets me catch these legends again in Max Lair
Solgaleo - F75B3E5F - 5001 Bool
Xerneas - F75830BB - 4995 Bool
Edit:
These are the rest of the legends:
The TRUE ones are those checked manually the rest are most likely correct though
My save file is Sword (1.0 -> 1.2 -> 1.3 Save) btw