Downgrade PSP 3000 v. 4.21

Hey all...
Is there any way that I could downgrade my PSP 3000 version 4.21 without any pandora batt??
If Yes, can u guys help me out with it.
If no,wad is needed to downgrade my PSP??
Hope u guys out there could help me as i m unable to buy the Pandora's Batt.

You cannot put true CFW on a PSP-3000..

You need to use davee's chickHEN r2 > CFE enabler or one of the GEN,MHU fw's.

Use - http://forums.exophase.com/showthread.php?t=10806&highlight=chickHEN

and http://forums.exophase.com/showthread.php?t=10994&highlight=chickHEN although a 5.50 GEN and MHU FW are out there as well.