Using 3.XX OE Recovery Mode
By SpongeFreak52

NOTICE: There have been errors reported with custom firmware 3.80 and up. Using on higher firmwares is not suggested.

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Okay, so you've installed a custom firmware, right? Good for you! But what happens when you've made a flashing error? This can happen when you make a mistake changing your gameboot, coldboot, font, menu icons, etc. Your PSP might not be able to even boot properly! Luckily, there is hope for you! Thanks to the great Recovery Mode included with custom firmwares, you can easily downgrade back to firmware 1.50, and start all over. But how do you use it? Well, my friend, you've come to the right thread!
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NOTE: This tutorial involves modifying your PSP's Flash0 (where the system files are stored). Improper use of the Flash0 can lead to a permanent brick. Please proceed with caution.

First off, you'll need to know how to get to recovery mode. Easy! When starting up your PSP, hold in the R trigger until you see a bluish-purplish screen, giving you several options. Okay, now that we've got that settled, let's get to fixing your PSP!

1. First, you'll need to download my ready-to-go recovery pack, which you can get HERE.

2. Next, extract the folder named "RECOVERY" into X:/PSP/GAME, where X resemble's your PSP's drive letter on your computer.

3. Okay, now boot up your PSP while holding down the R trigger. Recovery Mode should eventually appear.

4. Now, go to "Run program as /PSP/GAME/RECOVERY/EBOOT.PBP"

5. Hit X. The downgrading process should now begin. If all goes well, you should now have firmware 1.50. Now if you want to, you can head back up to an OE firmware, or you can stick with 1.50, it's your choice.

Okay then, you're all set! Hopefully this tutorial has helped!

If you have any questions, feel free to PM me. I will be happy to help!