Upgraded my FW by accident to 5.55 - Need to downgrade :(

Hi guys

I have a PSP 1000

I used to have it so I could download games and play them. I did it myself, maybe around a year ago. Don't remember what I did or the firmware I was using but I did it.

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Last week I got Raw V Smackdown 2010 and by accident I said yes to the FW update. Now my PSP is running on 5.55 Firmware which I got from the UMD Disc.

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Now I can't play/download games.

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What are my options?

Can I downgrade from 5.55 to something else?

I'm noobish to this things, if I follow a guide I can do something but I'm a noob too.

If there is a way purely with software I can do would be great

If I have to go and buy a pandora battery or something, then if someone could link me to a good place to buy one that ships to Switzerland, let me know

Thanks!