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!
Look guys, I have a problem. I bought my PSP about a month ago, and it came with firware version 2.0. I had no clue what that meant back then. So when I saw that there was an update I went for it. Now I know what it did. So what I am asking is, does anybody (and I mean ANYBODY) know how I can get back to firmware version 1.5 FROM a version 2.60? That would be much appeciated. Also, if you can’t help from 2.60 to 1.5, what about 2.60 to 2.0? Because then I can try this method above ^^^ Thanks Guys!
Look guys, I have a problem. I bought my PSP about a month ago, and it came with firware version 2.0. I had no clue what that meant back then. So when I saw that there was an update I went for it. Now I know what it did. So what I am asking is, does anybody (and I mean ANYBODY) know how I can get back to firmware version 1.5 FROM a version 2.60? That would be much appeciated. Also, if you can’t help from 2.60 to 1.5, what about 2.60 to 2.0? Because then I can try this method above ^^^ Thanks Guys!
UMMM… maybe this is stated and im just really really stupid but… does the battery have to be full?
thx for an answer
I cant even get outta the horses gate, I have a 1.52 Psp, and for the life of me cant find how to upgrade to 2.0, so i can get back to 1.5
Afraid to just update cuz it might go past 2.0, lost a former Psp that way, any help out there pleez.
Can anyone give an answer for the screen freeze and switch off when I go to the photo menu???
I have followed all the instructions,put everything in correct folders.What’s wrong???I’ve checked a million times!!
Iv’e checked all of the posts and nobody gives a definate answer.
If anyone does know can you email me flutterjo@yahoo.com I’ve tried soooooo many times!!!
lol no offense, but despite my earlier comment about not understanding if the battery needed to be full, i have downgraded 2 psp’s using these files AND i scanned them with NOD… no trojan period. the fact that i have only read two problems with this virus, makes me come to the conclusion that these people are making it up. I will not say that this will always be safe, but i downloaded three or so days ago, and there was no virus.
YES, i did it!!! i just tryed it the first time and it work!!!!i didnt add any thing else than what the origin tutorial said :)
#250:
how can it freezz your PSP if there is no virus on it?? :)
just disable the AV during the steps.
i want to downgrade my psp from 2.0 to 1.5 but dont want the risk of bricking it up and losing my psp has anyone figured out how to unbrick it or what bricking actualy is doing to a psp
Hey guess wat i found out? u can get homebrew on v2.0. ive got 2.0 n i can still play homebrew
hi guys….i’m sorry to say but i am really new to this…anyway i seem to be unable to put video from my computer onto the psp…i have converted it but i think with my playing i have deleted a folder somewhere…i have the music folder games etc but where do i put video…..and finally will i be able to downgrade from v2.01….or help gratefully recieved.
hi guys….i’m sorry to say but i am really new to this…anyway i seem to be unable to put video from my computer onto the psp…i have converted it but i think with my playing i have deleted a folder somewhere…i have the music folder games etc but where do i put video…..and finally will i be able to downgrade from v2.01….or help gratefully recieved.
what can i say ! AWESOME ! 37yr old truck driver from UK. i done it followed instructions carefully and it worked perfectly!!
Anyone with the nerve and care CAN do this.
i went from a UK version 1.52 >2.0>1.5 took me about 5mins or so.
Well Done to these guys, AMAZING WORK !!
.ISOs inf***ingcredible!!
thank you
please please can you help me! iv managed to downgrade my psp to v150 but dont know how to put the umd emulator together to run games iv got it down in writing what to do just dont understand!!!!!!!??????
Does this work with downgrading from v 2.60 ??
It works pretty goo thx
Help… I cannot find the psp/game folder… how can I find it. I currently am running v2.00.
I downloaded EBOOT.PBP but when i try to unzip it, it says that it’s corrupted. WHYYYY?? Does anyone knows where i could download that file?
I tried your instructions here on my PSP 1.52, but I could not find the “overflow.tif” in the “/PSP/PHOTO” folder?
I assume your instructions only work on PSP 2.0 firmware. If that is true, can you please tell me where to download 2.0 firmware and the instruction of upgrading my 1.52 to 2.0. Once upgraded to 2.0, I can follow the instructions here to downgrade from 2.0 to 1.50. Thanks.
Hi
can someone please help me !!!!!!
Followed all the instructions to the letter but every time I go into the photo menu, it just freezes before I can highlight the icon and after a few seconds turns itself off. Have read all the feedback and tried all suggestions but nothing is working. My psp is a japaneese version 2.00, any suggestions will be really helpfull as i am ready for jumping on it.
Thanks
jay.soper@ntlworld.com
where the hell is that overflow.tif?
I don’t see any.
i downgradeded my psp but when i try to start up emulaters it shows the start up logo en cuntinus and then sez error cannot play file
i dont now what i did wrong evretimg exept homebrew works heelp please
Ok now ive been on loads of site’s l8ly .. i bought my son a psp for christmas, it came with version 2.00 allready on it ,i was thinking of downgrading it but I have read that they have allready cracked version 2.00 as u allready know its called “HelloWorld” so is it really worth downgrading ? is there any homebrew games for 2 yet ? im new to all this and havnt a clue really .. i just dont know what to do for the best coz i dont want to f*** my son’s psp …. if someone could put there email addy so i can talk to them on msn about downgrading and the psp that would be great thanx xx
oh and forgot to say that Ive tried what it said @ the top of the page and it didnt work 4 me, my psp just froze,then went black (no white writing)then turned itself off ….. so im lost now … :(
HI Can somebody help me PLZZZZZZ!
Im tryin to downgrade my psp, and i can follow all the instruction up 2 the part where u have 2 copy the overflow.tif file, i simply can not find it any where:S! PLZZZZZ HELP ME I NEED TO DOWNGRADE:(
hi everyone i have version 2.01 is there any sort of downgrade for it yet so ican play homebrew games!!!
GUYS, HERE IS HOW YOU FIX THE PROBLEM! RE FORMAT YOUR MEMORY STICK THEN REPLACE ALL DATA, IT WORKED FOR ME
The PSP Bricker Virus is on ALL overflow.tif files. IT SHOULD BE. The Virus is the reason it is possible to downgrade. This Trojan.PSP.Brick WILL NOT HARM THE PSP but it will allow it to be downgraded. Also If the PSP Freezes, just take out the battery and reboot it.
omg #250 ur a idiot READ THE TOP OF THE PAGE!!!
ive just downgraded without any problems…i think…..i hense Think, as since doing this i now have a boring grey background which i dont seem to be able to change, cant even select my d/l home piccies, has any one else occured this problem,
hey will this work with version 2.5??? if so e-mail me at Ty_905@hotmail.com
Where do you stick your hacks, like what folder,
i have the codes, but can you please tell me where i put them?
ok got this problem i did everything correctly. when i go to the photo icon in my psp it freezes then after 11 seconds everything closes what do i do? I gets a black screen but it automatically closees the power. Help me
nevermid i put the index and h.bin in the wrong folder hahaha its been two days and its all in here
hi, i have got a psp and ive done this but my psp is at the momented upgraded to version 3.5 but i cant downgrade dow 1.50, i have the file on my game/memorystick and i have the overflow picture but it dosent work??? can any1 help me? dus any1 have a website 4 me to use or tel me wat im doin wrong??? ta
I just downgraded from 2.0 to 1.5 after been looking for long time ago, this thing really works great like Eliot Phillips said, thank you very much.
If that link don’t work, I found those files in the next address too:
The MPHDowngrader.zip as 164_MPHDowngrader.zip, but the same in
http://dl.qj.net/index.php?pg=12&fid=164&catid=114
and the EBOOT_1.50.zip can be download just click here
http://www.gamefreax-forum.de/files/EBOOT_1.50.zip
Good luck and read everything step by step
help my psp. thanks !!!!!
Hey can you tell me what is MPHDowngrader.zip ow do I use it and where to find it I have 3.4 also what is overflow.t where do I find it and what does it do
hey can anyone tell me pls how can i downgrade my psp from 3.50 to 1.00 or 2.00, here is my mail address intrareatriajului@yahoo.com or u can add me on msn robertocrack007@hotmail.com or on yahoo roberto_crack007@yahoo.com pls help me 0_0 !!
My norton anti-virus stops the overflow.tif. Is it possible to downgrade without screwing with norton anti-virus?
can anyone help me i need a firmware downgrader for 3.5.2 to 1.5 please help!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
this site rocks! I’d rather promote this in my website. http://www.openpchelp.com
I find a article about how to Downgrade Your Psp to Version 1.5 just Using Your Psp Battery
http://www.wikihow.com/Downgrade-Your-Psp-to-Version-1.5-Using-Your-Psp-Battery
tam n, you are getting that error because you have the new model of the psp (aka ta-082+ motherboard). Those psps start at about 2.00 and cannot be upgraded from below 2.00 sorry :(
THANK!!!!!!!!! it rely work. U can find the missing file
in Google.