This guide will teach you how to use emulators on a PSP with official firmware 5.50 and higher. I am testing this tutorial on a PSP-1001 so if you could please test it with an unhackable PSP and post your results it would be much appreciated. Also, do not post links to copyrighted material, it is heavily frowned upon.
Things to download:
Patapon 2 demo - download link
The specially crafted game save used to trigger the HBL - download here
Latest version of HBL (rev94) - download link
mh gpspkai - download link -
uo_Snes9x_002y32 - download link -
psp2600 - download link -
For more emulators please visit the homepage of this tutorial which is on PSP-Hacks. I update that page more often than I update this page.
Setting up the Half Byte Loader
Format your PSP's memory stick from the PSP before you do any of this. Formatting your memory stick will erase all of your data so make sure you have important stuff backed up. Don't put anything on the memory stick until I say so. Connect your PSP to your computer via USB or by using a card reader. Open the hbl-r94-wololo.zip file on your computer extract the contents of it to the root of your memory stick.
Open the game save archive (UCUS98732_DATA02.zip) on your computer and extract the contents of it to your memory stick. The UCUS98732_DATA02 needs to go in \PSP\SAVEDATA\. Don't use the h.bin from that zip file, I'm not sure what it's for. You get a h.bin file from the hbl-r94-wololo.zip archive which is the one I'm using.
Then you need to open the Patapon2 archive on your computer. You should see a folder named UCUS98734. Copy that folder to ms0:\PSP\GAME\.
Put the emulators in the ms0:\PSP\GAME\ folder. For the GBA emulator you need to search Google for a file called gba_bios.bin. This goes in the folder with the GBA emulator's EBOOT file.
Launching the Emulators
Disconnect the PSP from your computer. Start the Patapon2 demo on your PSP.
Answer "No" to the first question and "Yes" to the second question (when it asks you about not finding any save files).
You will then get to the Patapon's main menu, click Continue.
Load Wolo's save data. Then you will be presented with a load screen that says HATAPON'S MARCH. When it's done loading it tells you to press any button. I press R but I believe it doesn't matter what you press here.
Once you get to the next screen press R and the Half Byte Loader will start.
You'll be presented with a menu listing all of the homebrew you have in the \PSP\GAME\ folder. Select your emulator and start playing your favorite games!
Specific emulator tutorials. These are a bit more in depth.
Amiga - here
GBA - here
SNES - here
N64 - here
HBL working on PSP 3000