I tried installing 6.61 PRO C2 and infinity v2.0.3 on my psp 3001 (following the instructions on the CFW guide of this subreddit) but it just shows corrupted data when I disconnect,
Release: Infinity 2.0 – Enables Permanent 6.6x Custom Firmware for all PSPs! - Wololo.net
Update from 6.60 PRO-B9 CFW to PRO-C2 on PSP 3000 | PSX-Place