This next hack is pretty, cool, I’d say. It uses weapon Ability Byte 0x80 to allow an item with a stat boost pointer to give those boosts even not equipped! Now you can have an actual Starsphere in your hack.
Optionally, you can use a version that prevents multiple items from boosting the same stat; it’s included in the downloads. You can still have an equipped weapon + passive item boosting the same stat.
Old download for FE7
Old download for FE8