Impossible on a PSP 3000/Go/Street. Infinity 2.0 does not touch the "IPL" (initial program load) on those models. On a PSP 1000/2000, if you brick, use a Pandora Battery + Magic Memory Stick to recover. The MrMario pack is tested to avoid bricks.
Search YouTube for “MrMario2011 PSP Infinity 2.0” – his video description contains the official, safe download link. Avoid random “CFW installer.exe” files from untrusted forums. psp 6.61 infinity 2.0 cfw pack by mrmario2011
Warning: While this process is generally safe, modifying flash memory always carries a small risk. Proceed with caution. Impossible on a PSP 3000/Go/Street
Important: This pack is for educational and backup purposes only. You should only install CFW on a PSP you own, using game backups you legally own. Piracy hurts the hobby. Important: This pack is for educational and backup