You heard right folks. It is now possible to run homebrew on all firmware versions. The Noobz team found a “goofy” exploit a few short days ago and has now released a downgrader for firmware version 3.03 (the latest). The exploit takes advantage of a kernel mode hole found in the old GTA exploit that wasn’t patched properly. To downgrade you will need an unpatched copy of GTA: LCS, a PSP with firmware 3.03, the downgrader files, and a 1.50 EBOOT. Once downgraded, you will be able to run homebrew as you please or you can upgrade to a homebrew capable custom firmware.
If you don’t feel like you’re ready to make the downgrade leap, the Noobz team has also create HEN 3.03 which installs a temporary patch in the memory of the PSP and puts it in a 1.50-esque state allowing you to run homebrew almost as if you had firmware 1.50 installed. The only downside is that the patch goes away after the PSP is fully restarted, so you will have to run it each time you turn on your PSP. Note that the patch persists in sleep mode. You will still need an unpatched copy of of GTA: LCS for this.
To determine whether a copy of GTA: Liberty City Stories is patched or not, look at the firmware update included on the UMD. If it contains the 2.00 update, it is unpatched. Patched versions contain higher version updates.
Please note that while the Noobz team has tested this exploit to be highly successful, there is still a small chance of brickage as usual with all homebrew that modifies the firmware of the PSP. If you are ready to take that risk for the sake of homebrew, checkout PSP Updates for more details and the installation procedure.[via PSP Updates]