This patch is meant to make the game a bit easier and less frustrating.
Applying this patch to Mega Man 4 will make the weapon energy of all weapons restore fully whenever a life is lost.
This mechanic is officially applied in Mega Man games for the PS1 and later.
Situations where this primarily affects the game:
During boss fights
Cossack Stage 1
Cossack Stage 2
Wily Stage 1
Wily Stage 2
ROM / ISO Information:
Database match: Mega Man 4 (USA)
Database: No-Intro: Nintendo Entertainment System (v. 20180803-121122)