Possiblity for downgrading?

OK I have actually know about homebrew for a while but have actually never tried it. Then when I decided to try things out I realised Sony put firmware 2.81 on my PSP. (A while back I accedentally bricked it and lucky for me it was still under warrenty so I sent it in.) Now realising my PSP is usless for Homebrew I decided to think of possibilities of ways to downgrade it. Thus comes to my idea.

Is it possible to take apart a existing PSP firmware like 3.03 so that you have the part of the file that the PSP will reconize as the update. From there put a custom firmware or something on the file with the seperated "identity" so this way the PSP will go into the update mode but install the custom firmware because you switch it out with the custom one?

Sad to say I lack the know-how to even attempt to do this or the hardware specs to know if this is possible.

In all just an idea, sorry if I come accross as to much of a new person at this.

ur pretty much out of luck, there is no way to downgrade as of now. you will have to wait until a downgrader comes out, but that could take a long time... the 2.80 downgrader just came out, imagine when 3.03 downgrader is gona come out, they have to go through all the versions in order to downgrade

That's the general idea already.
Problem is once you change the 3.03 update this breaks the signature check of the file.
The PSP will not execute the file.
Even if you can get it to execute its dangerous
and will probably brick your PSP unless you know exactly what you are doing.

What must happen first is that the PSP must be tricked into running unsigned code.

This is called an exploit, which is something like a picture file
or something else that causes the PSP to go into a crash, open, state
that allows full access to the kernal (OS) of the PSP.

Once this is possible then the arduous work of creating a down-grader that won't brick the PSP can begin.

Your best best until an Exploit can be found is to have a UP mod chip installed.
This takes far more than basic soldering skills.
This ain't the old playstation or xbox we are talking about.
(Micro-Soldering)

There are a lot of folks with a 2.81 PSP that are patiently waiting for a downgrader

OK to a degree I figured changing an actual firmware would require more work than the average modification. Then on to the next question(s).

Same thought as before but is it possible to load homebrew using an existing PSP demo's signature? But I'm probally goig to assume that the same is true even with the demo's that if you change something it alters the signature as well.

If that isn't a possibility would there be a way to load homebrew on any of the video formats so when it loads the movie it loads the homebrew instead? Then again with how close that is to the TIFF exploit Sony might of already caught something like that.

O well I'm just trying to people spark ideas on where to try start at for finding homebrew methods.

It would be great if someone managed to steal Sony's digital signature and then be able to sign our own eboots so they run on any official firmware. Unfortunately, that's close to impossible to do that because it requires reverse engineering the 1024 or 2048 bit RSA signing hash. Well, I think so anyway...

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Originally Posted by YKB

It would be great if someone managed to steal Sony's digital signature and then be able to sign our own eboots so they run on any official firmware. Unfortunately, that's close to impossible to do that because it requires reverse engineering the 1024 or 2048 bit RSA signing hash. Well, I think so anyway...

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even if that happened [ it won't] any homebrew which used the signature would be illegal. and sony would take drastic attacks on users

a 2.81 downgrader wont be too long now tho, surely. a couple of months maybe tops. at least it wont be as long as for 3.xx downgrader tho, that will be like at least a year.

Quote:

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Originally Posted by gdf

a 2.81 downgrader wont be too long now tho, surely. a couple of months maybe tops. at least it wont be as long as for 3.xx downgrader tho, that will be like at least a year.

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Oy crap (And I did upgrade to 3.01:mad: ) well. Oh well most of the other ways I could think of probally would end up into reverse engineering so I call my ideas at a halt for now until I think of any more.

Who knows mabye they will find a hole in 3.xx that will work on 2.81 as well. So until then I guess I wait or start shopping around for a PSP that can use homebrew.

u can downgrade any firmware, as long as u have the U.P. chip. the chip actually isnt all that special, the main thing is that u have flash access directly from your computer