This is just a simple hack that replaces the GBA battle courses with the SNES battle courses, which were originally cut from the game, fixing the bugs that they originally had.
Patch over a US version of the game.
Database match: Mario Kart - Super Circuit (USA)
Database: No-Intro: Game Boy Advance (v. 20210227-023848)
File/ROM SHA-1: 9D327C030C3E2D9007990518594F70C3340AC56F
File/ROM CRC32: ED316E37