Introduction to PSP Homebrew
This is where the homebrew community comes in. With some modifications to its system software, the PSP can run 3rd party software, just like an ordinary computer. A massive community has sprung up online that is dedicated to these modifications. Read on to find out more.
In the beginning
When Sony first released the PSP, it had no restrictions. It was possible to write 3rd party software and install it to a memory stick. The PS2dev community created a homebrew development kit for the new system, and the community of developers began to grow.
After a while, Sony started to realize this was a problem. Although 3rd party utilities and games were harmless, they realized it was possible to run commercial games from the memory stick as well, using homebrew ISO loaders. Sony knew that this could hurt their game sales, so they issued firmware version 2.0, which removed this functionality. In this version of the firmware, and every subsequent release, it is impossible to run anything but UMD disks and official game demos from Sony. While this makes piracy impossible, it also dealt a serious blow to the burgeoning homebrew community.
A new hope
In late 2005, Homebrew developer Fanjita discovered a tantalizing hole in Grand Theft Auto: Liberty City Stories. By copying a special hacked game save to the memory stick and loading it in GTA, it was possible to purposely crash the PSP, and load custom code! For the first time since the release of firmware 2.00, it was possible to run homebrew code again. At the time, PSPs with firmware 1.50 were in high demand, and supplies were dwindling. Using this software exploit, Fanjita and the Noobz team were able to create a "downgrader" for the current firmware, version 3.40. It became possible to downgrade any PSP, as long as it had nothing higher than 3.40, to the older 1.50 firmware, and thus use it for homebrew once again.
Sony catches on
Sony was none too happy about this exploit. They issued a recall on GTA:LCS, and sent new, patched copies to stores. They also began releasing firmware updates in the game disks themselves. Newer games required newer firmwares, and so homebrew users had to choose between a fully functional PSP, or a crippled system that was compatible with newer games. As always, the scene found workarounds, specifically a program called Devhook, but it was confusing and complicated to set up.
Enter Dark Alex
A hacker known as Dark Alex developed a compelling solution. He designed a software package which, when installed on a PSP running the 1.50 firmware, allowed the user to install a hybrid firmware of his own design. In other words, a PSP with Dark Alex's custom firmware has all the features and functionality of the standard Sony firmware, in addition to support for firmware 1.50 based software. The firmware also came with something called "HEN", short for Homebrew ENabler. Developers could create software for the familiar 1.50 firmware, or the newer 3.XX series this way.
Custom Firmwares today
Dark Alex has continued refining his custom firmwares, and has managed to keep up with every major release from Sony. His latest stable firmware, M33 3.80, is the most advanced version yet. It boasts tons of new features including a custom devkit, support for a 1.50 kernel plugin, and most importantly, a hacked network update system. In the past, running network update would upgrade to the vanilla Sony firmware, removing homebrew functionality. However, in M33 3.80, it because possible to update to newer custom firmwares with Sony's own tool.
We hope you enjoyed our little history lesson. Stay tuned for the next installment in this series, in which we will give you detailed, step by step instructions to safely install the custom firmware on your own PSP!