2.80 downgrade idea - PSP3D.com - Sony PlayStation Portable News, Homebrew, Hacks, Reviews, Videos, Mods, Forums

kodan50 · #1 (**permalink**) 10-13-2006, 01:34 AM

Okay, I don't want to stir up any negative feelings with this thread, I just have an idea, and I want to know if it is a possibility or not.

I am relatively new to the PSP homebrew / FW / hacking scene. (I would say, a couple weeks or so when I actaully started using homebrew on my 2.50). Okay, so I have 2 PSPs, one is a 2.50 with the TA-082 mobo and the other is a 2.80 with a normal mobo. I want to downgrade that to 2.5, and after reviewing a lot of information, I have an idea. Here it is (and LOTs of feedback to its possibility would be appreciated!)

Well, first I tried getting the PSP to see an update and try to run it. Using PBP unpacker, I changed the update to look from 2.5 to 3.5, and the PSP started running it. It obveously went back to the main dashboard and said it cant run it. Okay, that was expected. Then I tried using the 2.81 with the 2.5 update information to see if I can trick it into working. Again, failed. I have one final glimpse of desperation to finally get back to 2.5 on my PSP.

If I run the 2.81 update it will take me to the "press X to start update" screen. If I remove the memory stick, it returns to the main dashboard with the "Update failed" error. I have the idea that if I try to modify the update file, while still being at the update screen, I want to convince it that it is updating to 2.81, but instead use the data from the 2.5 update file that I want to put into the file using the PBP unpacker program.

So, if this makes any sence what so ever, then here is a couple questions:

1: Is it possible to hot-swap the memory card, or at least not let the PSP know its memory card was removed and then reinstalled?
2: Let's say I got the memory card out, and was able to update the update file, if I replaced the files that contained the 2.5 firmware, will it still accept it thinking its the 2.81, or will it crash?
3: Would the Datel hard drive be able to be removed and then reinstalled w/o breaking the adapter? (I am talking about the hard drive removed from the adapter unit itself, not the adapter from the PSP)

I just don't know. I tried looking around but couldn't seem to find any information regarding possibility to hot swap, or if the hard drive can be safely detached from a "hot" adapter.

Christen · #2 (**permalink**) 10-13-2006, 01:39 AM

People have tried hacking the update eboots before, and from what their results have been it simply does not work. However keep on thinking up ideas you never know when one would work!

psplaya · #3 (**permalink**) 10-13-2006, 02:44 AM

1. No
2. Will Brick ya PSP
3. Dunno

Hotswap method was thought of a LONG time ago, b4 the oifficial 2.71 downgrader their was a "supposed unofficial 2.71 downgrader" where the hotswap method took place, it ended up just bricking psp's.

jcoolkatzerg · #4 (**permalink**) 10-13-2006, 04:30 AM

Quote:

Originally Posted by kodan50

Okay, I don't want to stir up any negative feelings with this thread, I just have an idea, and I want to know if it is a possibility or not.

I am relatively new to the PSP homebrew / FW / hacking scene. (I would say, a couple weeks or so when I actaully started using homebrew on my 2.50). Okay, so I have 2 PSPs, one is a 2.50 with the TA-082 mobo and the other is a 2.80 with a normal mobo. I want to downgrade that to 2.5, and after reviewing a lot of information, I have an idea. Here it is (and LOTs of feedback to its possibility would be appreciated!)

Well, first I tried getting the PSP to see an update and try to run it. Using PBP unpacker, I changed the update to look from 2.5 to 3.5, and the PSP started running it. It obveously went back to the main dashboard and said it cant run it. Okay, that was expected. Then I tried using the 2.81 with the 2.5 update information to see if I can trick it into working. Again, failed. I have one final glimpse of desperation to finally get back to 2.5 on my PSP.

If I run the 2.81 update it will take me to the "press X to start update" screen. If I remove the memory stick, it returns to the main dashboard with the "Update failed" error. I have the idea that if I try to modify the update file, while still being at the update screen, I want to convince it that it is updating to 2.81, but instead use the data from the 2.5 update file that I want to put into the file using the PBP unpacker program.

So, if this makes any sence what so ever, then here is a couple questions:

1: Is it possible to hot-swap the memory card, or at least not let the PSP know its memory card was removed and then reinstalled?
2: Let's say I got the memory card out, and was able to update the update file, if I replaced the files that contained the 2.5 firmware, will it still accept it thinking its the 2.81, or will it crash?
3: Would the Datel hard drive be able to be removed and then reinstalled w/o breaking the adapter? (I am talking about the hard drive removed from the adapter unit itself, not the adapter from the PSP)

I just don't know. I tried looking around but couldn't seem to find any information regarding possibility to hot swap, or if the hard drive can be safely detached from a "hot" adapter.

1: Yes, it's possible, but the psp update performs many many data checks as it is running to prevent this from happening.
2: It just gives an error. Once again, this is due to the many checks in the updater(s).
3: I'm not sure, but I highly doubt it will work.

I'm not trying to flame you when I say this, but there is a rule of thumb to keep in mind with downgrader ideas: If it sounds easy, then it won't work. If it really was that simple, don't you think that the master devs would have thought of it (and tried it) and Sony would have tried to block it?

FreeJ · #5 (**permalink**) 10-13-2006, 04:56 AM

the only question i have is why doesnt it work?

jcoolkatzerg · #6 (**permalink**) 10-13-2006, 05:03 AM

Quote:

Originally Posted by FreeJ

the only question i have is why doesnt it work?

The psp runs a checksum just before the update proccess (the actual firmware flasher part) starts that makes sure that the eboot hasn't been modified in any way. Hex editing, swaping, or anything else causes it to:

Fail
Crash
Brick

(By the way, it's not just a checksum, but a few other verification proccesses too. For more detail, ask Freeplay.)

SpongeFreak52 · #7 (**permalink**) 10-13-2006, 08:12 AM

There is no way you can get the MS swap method to work. It has been proven to be impossible, and yes, the PSP performs many checks before, and even during the update, so it would know and immediately abort, even if it has to result in a brick.

dorkdork777 · #8 (**permalink**) 10-13-2006, 11:52 AM

That method has been tried many times before, and after many tries and bricks the majority of the community has just accepted the fact it's impossible. The only time it's actually worked was with KXPLOIT's predecessor, Swap-aloit, but that was on 1.50 only.

kodan50 · #9 (**permalink**) 10-15-2006, 05:40 PM

I know this seems pointless, I have quite a bit more understanding after watching my PSP function with this experiment. I will continue my campaign against Son'y 2.80 firmware and see if anything is possible. Also, I read a lot about threads and processes being ran in the background of the PSP service. I will see if I can get at least a single thread to run w/o "crashing" .. It is too bad that we don't have kernel access. I wonder if some kind of thread, or process will activate this ability, much like the official updater I guess. I wish I wasnt such a noob at hardware, otherwise I would try more....

As for this idea, I wont scrap it until I brick my 2.80 ... (If I do then I got Flash0 access ...)

pspoopy · #10 (**permalink**) 10-15-2006, 07:07 PM

personally i wouldnt brick my psp......a downgrader will come soon enough