While the maximum damage a character could deal to an individual monster in a single attack in pre-PS2 Final Fantasy games was always 9999, the maximum damage Final Fantasy IV can actually handle is 16383 (that's 3FFF in hex).
This mod unlocks the artificial damage cap and reworks the sprite coding to allow display of the fifth digit.
You finally have a reason to cast Meteo after acquiring Bahamut!
Final Fantasy II (U) [!] (v1.1).smc
CRC-32: EE345FBD
SHA-1: C0E02B0F44CCA882C0AEE5C16FF41EDB6B79FA71
SHA-256: B96BA10252C4C0359CB05976E1A275BC7B0C3D1917DFD49BF6AFAAB84CF12B83
MD-5: E27E0ADB7CF09A9497A22AB96445D1B9