Code 020128020D will load a pattern test screen, which was removed from the Japanese version.
Sound Test Text
Present at 0x05006C is text for a sound test. The sound test no longer exists in the final releases.
<< SOUND TEST >>....UP -, DOWN +....No:
The build date of the game can be found in the ROM. Offsets are written below each region:
0x50928 - 0x5094F
0x70BC8 - 0x70BF3
WSB Version 0.9.3 Dec 28 2001 18:31:06
G9_GBA Version 1.0.0 May 29 2002 15:50:33