How to Mod a PSP to Custom Firmware | Super Easy | 6.60 PRO-C | Tutorial... : r/psphacks
Permanent 6.6x Custom Firmware For All PSP's! - Forums
PSP Custom Firmware 6.00-6.61
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Infinity 2.0 released for the PSP, allows for persistent CFW on all models of PSPs on 6.60 and 6.61 | GBAtemp.net - The Independent Video Game Community
The last missing piece: Permanent 6.60 CFWs for all PSPs in near future!? - Wololo.net
PSP Custom Firmware 6.00-6.61
4 Ways to Upgrade Your PSP Firmware - wikiHow
PRO Firmware PSP - GameBrew
Hack, Install Custom Firmware on Sony PSP-E1004 Street
PSP 6.61 Custom Firmware Install on any PSP - PSP, PSP Slim, PSP 3000, PSP Go & E1000 | Page 11 | Digiex