UPDATE: Since this how-to was first written things have changed. Sony has released firmware 2.01 which makes this downgrade impossible. A PSP bricker trojan was released because of this antivirus software will classify both the good and bad downgrade files as harmful. You should do more research into the current state of the downgrade before attempting. As far as we know our firmware links are still good, we are not hosting them so we can not vouch for their safety.
C.K. Sample, III, TUAW / WIN Blogger and author of the forthcoming book, PSP Hacks, got his hands on the version 2.0 downgrader and wrote up a thorough how- to complete with pics for us. He even takes the extra steps to upgrade and downgrade yet again, just to make sure such a thing is possible.
As you can see, I have 2.0 running with the browser on my PSP. 
Step 1: Download the downgrader from either here, here or here. Then make sure you get a copy of the original 1.5 firmware upgrader. I found my copy here.
Step 2: Connect your PSP to your computer via USB. On your memory stick, create a folder called UPDATE inside /PSP/GAME/ and place the EBOOT.PBP file from the 1.50 update inside this UPDATE folder.
Step 3: Unzip MPHDowngrader.zip. Drop overflow.tif into your /PSP/PHOTO/ folder. Put both h.bin and index.dat in the root of your Memory Stick.
Step 4: Disconnect your PSP from your computer and plug in the AC adapter.
Step 5: Navigate to Photo then Memory Stick via the PSP’s menu system and start scrolling down through your photos until you reach the overflow.tif picture.
You’ll know you’ve hit it when everything freezes and you get a black screen with a bunch of white text output.
If your PSP freezes without going to this black text screen, then hold the power button for about 10 seconds until the PSP shuts down, then hit the power button again to start it back up. Repeat this step until you get that black screen.
Step 6: Don’t panic. Hold the power button for about 10 seconds until the PSP powers off. Hit the power button again. Your PSP will start up, and if you navigate to your System Information, you’ll discover that your PSP thinks it is running version 1.0 of the firmware. It isn’t and you cannot run homebrew (yet).
Step 7: Navigate to Game–>Memory Stick, hit the X button, and navigate to the 1.5 updater. Make sure you have your PSP plugged in or the upgrade won’t work. Click the X button and update like you normally would. At the end of the upgrade you will receive an error saying that the upgrade failed and to contact Sony. Don’t panic. Ignore this and again force your PSP to power off and reboot.
Step 8: After the PSP reboots you will receive an error screen that is scary and confusing because it is in multiple languages. Don’t panic. Find the language you can understand and read the corresponding line. It notes that your preferences are fragged and that you need only hit the O button to restore some default-ish settings. Hit the O button. 
Step 9: The PSP will start back up and you will go through the initial setup like the day when you first bought your PSP. Do so and then go to the system info pane again, where you will see that you are rocking version 1.5. Run homebrew at will.
I ran through this entire procedure, then I downloaded the 2.0 update and installed that again, and then yet again went through the entire procedure again. It works like a charm. It’s a little time-consuming, but you can have the best of both worlds. Have fun!
How do i get the overflow past the virus protection…everytime i unzip it it gets deleted by the auto-protection…what should i do???
WHEN I TRY TO CLICK ON THE OVER FLOW FILE IT SAYS IT IS A CORRPUT FILE ON THE PSP
WHAT SHOULD I DO
PS WHAT IS BRICKING?
When i download the downgrader and i open it up in winrar I cant see it in the photo folder, i have redownloaded several times no change, can anyone please help?!?
Please do not keep repeating the downgrade frequently! It may work but continuously doing this process could be harmful to the PSP!
I reccommend that you only downgrade if you need to and once you have become bored of 1.5 and decide to upgrade DO NOT GET BORED OF 2.0 AND DOWNGRADE AGAIN!!!
Where do i put VSHELL PHOTO MENU thingy that it says in
the read me???
hi everything worked uptil the black screen with white letters, after that when i go to game update it says corrupted data..what shud i do?
thanks
please guys i need your help!!!
i keep downloading the MPHdowngrader from every site i can and i still can’t find the overflow.tif , i have looked for it everywhere and i even had like 5 complete “C:” search, (i mean that it looked for the file inside all the computer) i really don’t know what to do, could anyone tell me where is the overflow???? or even better send the file to my e-mail????
***** hoobastank_123@hotmail.com *****
Why the heck would I want to downgrade anyway???
Can anyone please tell me where i can download some games from… all the sites i used have shut down… Thanks in advance
I got bricked :(
And sony sends a new one to me so no prob with it only it costs 14 days!!!!
Anyone knows how to downgrade firmware from 1.52 to 1.50? Thanks!!
in step 6 my version is still 2.00
damn my bro messed up my psp he downloaded the 2.60 update will there be a way to downgrade from there cause the overflow pif doesnt work any more
It fucking works great fella’s :)
I started to hyper ventilate when i saw the error
But hey just restart and do it aggain then load the save game from the memory instead of the picture.
Great tutorial!
Norton Antivirus will class any overflow.tff as a virus,after the briking incidents. Just disable Norton while you do this hack and make sure you download from a site you can trust.
Norton Antivirus will class any overflow.tff as a virus,after the briking incidents. Just disable Norton while you do this hack and make sure you download from a site you can trust.
I run http://www.gamesconsoles.co.uk but we’re finding that we lose alot of business due to these dvd game sets you can get from ebay etc. so we are stopping doing these.
Personally, i use the copies as its just so much cheaper than the originals
My PSP doesn’t read any UMD disc would that matter??
I tried to downgrade my psp to 1.5 and after that I can’t switch it on. Help me pls!!!
HELP! I have SPS firmware v. 1.52
When i try upgrade it to v. 2.0, i have message: “The game could not be started. (80020148).
What is mean??
How i can upgrade psp?
PS: sorry for the bad Engl, i’m from Ukraine))
Is it okay to upgrade and downgrade a lot? I have Grand Thefth Auto for the PSP and it requires 2.00 but I also want to run my SNES emulator witch needs 1.50, so is it okay that if I want to run GTA then upgrade, but if I am feeling like playing some old SNES games to downgrade, tehn they next week I feel like GTA to upgrade ect ect ect. Is that okay for my PSP, or could it hurt it?
Hey, ive been trying this hack all day, and i cant get the software onto the psp. I have everything opened but i dont know how to put it all onto my psp, can some1 help me as soon as possible? email davepinsker@hotmail.com at any time, i really need your help.
Hey, ive been trying this hack all day, and i cant get the software onto the psp. I have everything opened but i dont know how to put it all onto my psp, can some1 help me as soon as possible? email davepinsker@hotmail.com at any time, i really need your help.
why does everyone want 1.5 ver. i have 2.6 is that bad?
help me please…
i bought a psp gigapack, he has v.2.01…
how can i install v.1.50??
please… need help
hey guys, ok im sh!t scared. I deleted the psp folder which it first starts on by accident :s and im afraid that i cant do this hack, please some1 email me as soon as possible davepinsker@hotmail.com
thanks
works perfectly! follow the directions and you’ll never brick a psp
works perfectly! follow the directions and you’ll never brick a psp
What is Homebrew?
is dere a way to downgrade the 2.5 firmware to 1.5 i heard from my friend that it can be done and a shop is charging $80…
please can some one help,, get to the photo step and freezes and turns off
some one help when i get to the photo stage it freezes and turns off
i’m scared if my PSP will brake. yet i’ll try it, if the downgrade successed for other people, then i guess i’ll do it. 1.50 here i come :)
I have a white japanese psp running version 2, can anyone tell me if they have done the downgrade on this, and if it worked. Any problems??? Thanks
you have to disable your antivirus mate as it thinks that the file is a virus but its not. Do some reading on google if you dont believe me.
Works like a champ! Great writeup!
im having trouble tryig to down grade… im following the directions, yet, im having trouble with step number 3… where i need to put those 2 files into the root of the memory stick… thats the only problem im having right now, cause i cant get the overflow file to show up in the photo browser…. need help please.
where is the “root” on my mem stick??
Didn’t read absolute all the comments but, I can help some… unless someone else already did it… I had the same thing, freezing when going to the tiff. image because…. I HAD A GAME INSIDE
SO TAKE OUT EVERYTHING YOU HAVE IN, then it works perfectly!
Merry Christmas all!
hello all just got a psp for xmas. honestly wanted it for emulation. but santa didnt no that 2.01 wouldnt do that so now im screwd nd stuck with 2.01 i wanna emulate :'( please help me if ne one finds a new hack for 2.01 which im sure some1 will eventully email me @ hackurpc@gmail.com please and thanks u.
I got to the stage when i had to select the file in the photo bit on my PSP and it just freezes i turned it off as said and tried it again, in fact about 40 times and it still didnt work! What is wrong????
what is the root of your Memory Stick? i canot get past this step can u help me please
I have the europian version of 1.52 firmware on my psp and was wondering if i will be able to downgrade my firmware from 1.52 to 1.5 and still be able to play english games that came with it???
this worked the first time for me. 1.52-=>2.0-=>1.5
took less than 5 mins from start to finish… thankyou… this is why the internet was created… spread the knowledge FREE!!!
will it delete game data on it i wont until i find out
I’ve just tried this using a PSP connected to a Mac Mini and it works absolutely fine. Everything was exactly as described in the tutorial, I just want to say thanks for sharing your knowledge with the world.
G.
first post!!!!!!
can the warranty cover a bricked psp?
HI CAN YOU HELP GOT TO UP DATE IT READS THE SYSTEM SOFTWARE ON YOUR PSP SYSTEM IS VERSION 2.00 THERE IS NO NEED TO UPDATE I HAVE SPENT ALL XMASS TRING HELP PLEASE
Help, I’ve bought one of those disks with games on for my son & Norton stopped the bricker’ virus. does anybody know where I can get a clean copy or have i wasted my money?