This hack removes both the full screen flashing that occurs when damaging a boss and the one that occurs when a boss is destroyed. There still exists some background sprite flickering when using the bomb attack.
Database match: Summer Carnival '92 - Recca (Japan)
Database: No-Intro: Nintendo Entertainment System (v. 20210216-231042)
File SHA-1: 4558A330119E79FCB50B46AE21B4171DA6623CE5
File CRC32: D98EC487
ROM SHA-1: 0CB2B28BAD1629F08BE5DE38DC8DF8BB66C78B3A
ROM CRC32: F31DCC15