PSP-Devolution

[Demon Cleaner]

Have you not even been tempted by the ability to play all the great PSX RPGs on the PSP now?

No. If I play them, I'd rather play on my TV than on a PSP. I'm no mobile gamer, only handheld I have is an MB Microvision from 1979 (already with exchangeable ROMs).

I played Valkyrie Profile:Lenneth on Oz PSP, it was pretty good, but seriously, I'm not gonna play a game for 50 hours on a PSP

[Submeg]

Ok, I have a PSP, and all these terms....

bricked: I'm assuming when you try to downgrade and you stuff it up and it becomes useless

flash: ?

So why do you have to downgrade it to be able to use it for emulation?

[Harrison]

OK, bricked means that basically it's as useful as a brick! This can happen if something goes wrong when you try to change the PSP firmware for a different version. Normally this would only occur if you didn't follow the instructions correctly or if the PSP lost power during the flashing process.

Flashing is the process of writing a new firmware version to the PSP's built in system rom, known as the NAND Memory.

Now the reason for downgrading. Officially released Sony games are "signed". This means they contain code that verifies they are official code. Much like every other console the PSP checks for this before it allows the running of a game.

One of the original versions of the Sony firmware, version 1.5, allowed the ability to run what is called homebrew code. This is code written without being signed. This meant that anyone could code something for the PSP, place it on a memory stick and run it. It also allowed people to write exploits to allow ISO copies of commercial games to run.

For this reason Sony quickly patched the firmware to stop the ability to run unsigned code and released firmware version 2.0. This is the reason people often talk about a 1.5 PSP as this is the only firmware version able to easily run unsigned code to get homebrew games, emulators or game ISOs to run.

Many newer versions of the PSP firmware have been released since the 1.5 version, and these contain a lot of new features not found in the older 1.5 release, such as the internet browser, or support for more image formats or higher resolution video playback. Also many newer games will only run on newer versions of the firmware. For this reason people have been trying to find ways to run "unsigned" code on each version of the PSP firmware that gets released.

The first method was via the Epsilon Undiluted Platinum Mod chip. This is installed inside the PSP and contains a second NAND flash memory chip. This allowed people to run two different firmwares at the same time, so they could have version 1.5 on one of the two NAND's for running emulation, homebrew etc... and also the latest version of the firmware on the other for the latest features. Then Epsilon took this further. They released a special BIOS that worked with firmware version 2.71. By installing PSP firmware 2.71 on the PSP's own NAND, and then installing a special Epsilon BIOS on the Unpiluted Platinum's own NAND memory it allowed the PSP to run all files as if it was a 1.5 PSP, but from 2.71. It did this by the Epsilon BIOS patching the PSP as it booted the newer 2.71 firmware. This worked well until Sony started to release games that then only ran on versions of the firmware newer than 2.71.

But the Mod chip is no longer needed since a hacker called Dark_AleX released a custom firmware at the end of last year. This new custom firmware is based on one of the latest PSP firmwares 3.03 so contains all of the latest features Sony have added. He gets around the running of unsigned code by combining the original 1.5 firmware with the 3.03 firmware when you run the program to flash the PSP with his custom firmware. Once a PSP has the custom 3.03 OE-C firmware installed it will allow you to run all homebrew games, emulators, ISOs and real games.

The custom firmware also includes built in support for the direct running of game ISOs. When using ISOs with the old 1.5 version you had to boot them via a program called DevHook, which took more time and effort. With the new Dark_Alex firmware you can directly just run any ISO from the memory stick without needing to do anything else.

The other big advantage of the 3.03 OE-C custom firmware is that you can run any PSX games on your Playstation, so you could for example run Final Fantasy 7, 8, and 9 on the PSP now!

Now to get a PSP to the magical 3.03 OE-C firmware, you first need to downgrade it to the older 1.5 firmware to allow it to run the code needed to them upgrade it to the custom firmware.

Until this week if you had a PSP with a firmware newer than 2.80 you were stuck as there was no way to downgrade these to 1.5 so you could then install the 3.03 OE-C firmware. But this week a new exploit was found in these newer versions and a new downgrader has been released that can downgrade any PSP back down to version 1.5. The only limitation of downgrading a newer PSP is you need the original release of GTA:LCS as this contains the exploit needed to run the downgrader to get the PSP back to 1.5. You can tell if the copy of GTA:LCS is the correct one as it will contain the firmware 2.0 updater. If the copy has a newer firmware updater then it won't work.

Finally, is there any reason to still have a mod chip in a PSP now that the Dark_AleX custom firmware does everything the mod chip can do and more. Yes, there is still a use. If a PSP gets bricked during a back firmware downgrade or upgrade you can recover it using the modchip. The Undiluted Platinum Mod chip includes a second USB connection that you can connect to a PC and use to dump a copy of the PSPs current NAND flash memory to a file, and you can also write one of these files back to the PSP to recover it. This is a very quick method to quickly get a PSP back to any version of firmware you have a flash image for.

Hope that answers any questions you have about the PSP, bricking, mod chips, running emulation etc...

If you are interested in getting the custom firmware onto your PSP so you can then run ISOs of commercial games, as well as emulators and PSX games then Oz has already created a guide on the forum that runs through most of what you need to know.

If you want a guide specific to your PSP, then let me know which firmware version your PSP currently has and I can run through exactly what you need to do.

[Submeg]

Cheers Harrison! That guy must be one smart mofo

[Submeg]

Oh yea my PSP has Firmware 2.7.1