1. Get FE8 U .gba rom
2. Get latest Hetja's Quest patch from the thread on Fire Emblem Universe
3. Apply .ups patch to .gba rom using a ups patcher like Rom Patcher JS (search for it online)
Updating
1. In-game,
Older than v0.7.07: just start a new game, the juice is not worth the squeeze
v0.7.07: From Off the Beaten Path, talk to Charon (the person you talk to when you want to go to the Labyrinth) -> Options -> Safely Update -> Yes and follow all of the instructions before updating
Previous Test Patch: From Off the Beaten Path, select Misc. -> Safely Update -> Yes and follow all of the instructions before updating
2. Get FE8 U .gba rom (DO NOT PATCH OVER YOUR OLD ROM)
3. Get latest Hetja's Quest patch from the thread on Fire Emblem Universe
4. Apply .ups patch to .gba rom using a ups patcher like Rom Patcher JS (search for it online)
5. Make sure new patched rom and old rom's .sav are named the same to retain your save file