1. Get PPF-O-Matic http://www.megagames.com/psx/psx_ppf.shtml
2. FTP to Xbox and erase cache files in X and or Z
3. Start Halo Sidewinder. When game starts reset xbox.
4. FTP again and grab the cache003.map file which will be in X or Z. 
5. Load PPF-O-Matic and patch the cach003.map file with one of these ppf files.
6. Then just shoot the patched file back to the xbox and start Sidewinder.