Look for preserved full sets of PS2 homebrew ELFs. MD5 Checksums for Verification
Try running the ELF from a different USB drive or ensure it's in the mc0:/BOOT/ directory.
Codebreaker requires a specific master code (M-Code) to hook into a game. If the game crashes after enabling cheats, verify that the game's region matches the cheat code region. NTSC codes will not work on PAL games. USB Drive Not Detected