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!
It Works Gr8! It takes 5 minutes. I went from 1.52 to 2.00, then down to 1.50. I have emulated and played ISO’s no problem! Lovely!
Advice to Everyone. Read the downgrade article at the top carefully and then ALL the comments first! There are many valuable tips and experiences mentioned!
Thanks Guys!
Norton only thinks its a virus cause it programmed to delete any file with that sort of script but rest a sure it isnt a virus i had the same problem so i turned my norton 2005 off.!! :)
i would like to know where i could find a version 2.0 update not a 2.01 could anyone one help me with that. :-)
#244 + #250 . I had the same problem with the overflow.tif. I just simply disabled my anti-virus. The tif file won’t damage ur pc or psp
omfg my psp is f**ked!
i have 2.5 update runnin any 1 kno how to downgrade that pain in tha ass…….appreciate it
do u need 2 disable the viris protection in order 2 Drop overflow.tif onto your /PSP/PHOTO/ folder?????….because when ever i try 2 do it it wont let me because it says theres a viris on it…..please help!!
If I downgrade, can i delete the photo that freezes the PSP?
The MPHDowngrader was developed partly by SonyXTeam. You can download the real version from here:
http://sonyxteam.com/modules.php?name=News&file=article&sid=5
I just did my new PSP yesterday and I had the same problem with Norton A/V. It seems that it is picking up the Overflow.tif file as a virus simply based on name and file size. My buddy, who had already done his was worried because every version we downloaded was getting an A/V trojan on this file. I wasn’t worried though, I just downloaded the one from sonyxteam, temporarily shut off my A/V and did the procedure on this page (also outlined in the readme from the ZIP file).
Thank you guys for your help. It has worked as you wrote. No problems. I happened exacty as your explanation says. It was really fast. Thanks again.
Thank you guys for your help. It has worked as you wrote. No problems. I happened exacty as your explanation says. It was really fast. Thanks again.
Downgrade works very well, all happened like explanation says. After downgrade tested games, films, pictures, music; erase all files on Memory Stick and put the new ones – no problem at all. I do not see any danger, except if you do not follow exactly explanation for downgrade.
Hey guys, can i do this downgrade if i have 1.52?
if not, does anyone have a direct link where i can download the 2.0 firmware, so i can downgrade to 1.50?
Hey guys, can i do this downgrade if i have 1.52?
if not, does anyone have a direct link where i can download the 2.0 firmware, so i can downgrade to 1.50?
Does anyone know if this will work with 1.52?
if not, can someone give me a direct link to download the 2.00 firmware so i can downgrade?
Anyone who has a Swedish PSP who made this hacking thingy work? I think im gonna do it but i want to know if it works with all regions of psp.
I just got a white psp from japan but it has 2.01 on it :( any ideas??
Regarding the MPH downgrader, overflow.tif, and Antivirus software:
New vius definitions on antivirus software have included Trojan.PSPBrick, which unfortuneately identifies overflow.tif as a virus and deletes it from your computer.
You need this file to downgrade!
To stop your computer from deleting this file simply open your antivirus software and exclude “overflow.tif” from all the various security checks in the options TAB. Your computer will no longer view this file as a threat and you will be free to do whatever you want with it… ie. Downgrade and run Homebrew!!! Yay!!!
I believe there actually is a PSPBrick virus out there so be careful, make sure you have the right file.
Just so you can check file size, my overflow.tif file, that I know is good and have used twice now to downgrade my PSP to v1.50 is – 16.6 KB (17,008 bytes)!
Hope this helps!
J
For everyone having trouble, use the 1.0 Final version of the downgrader. A newer and safer version of the downgrader was released, Google for [MPH_SXT]Downgrader1.0.zip .
It’s the 1.0 downgrader, newer and safer than the 0.9 downgrader everyone uses. It’s much easier to use, and the chances of bricking your PSP are much smaller…
I’ve used both downgraders, both work, everything went more smoothly with the 1.0 downgrader.
Also, overflow.tif isn’t a virus. Norton considers it as a virus because it contains misalanious code… so it’s considered a virus, but is the actual needed file, and won’t do any harm…
Unless your really stupid and don’t know what your doing, you’ll do fine, don’t worry about bricking your PSP, don’t worry about any virus, just follow the directions carefully.
I’ve upgraded and downgraded about 10 times now. :)
Is there any option, or program to change PSP MAC adress?It is necessary because i’ll be able to connect to somebody for free.(Sorry for my english)
am I about to brick my US PSP? I’m still concerned since the 1.5 firmware version is the Japanese version. If I choose to upgrade later from the 1.5 Jap ver. will I be able to upgrade to the US 2.0 Firmware version?
Are there any other catches about the 1.5 Jap firmware version?
Peter
am I about to brick my US PSP? I’m still concerned since the 1.5 firmware version is the Japanese version. If I choose to upgrade later from the 1.5 Jap ver. will I be able to upgrade to the US 2.0 Firmware version?
Are there any other catches about the 1.5 Jap firmware version?
Peter
there’s only three words i got for you: I love you
hey i downgraded from 2.0 to 1.50 and now i cant get back to 2.0 if i dont have 1.51 or 1.52 AND I CANT FIND THOSE DOWNLOADS ANYWERE if someone knows were to get 1.51 or 1.52 downloads please email me
when i tried to download the overflow.tif file my norton anti virus came up instantly deleating it so what can i do?
iam stuck on the MPHDowngrader.zip when i unzip it and try to drop overflow.tif into photos it says winzip was unable to extract ‘overflow.tif’, terminating operation
please can you help me.
Thank you
When i go to select the tiff picture in my memory stick this message appears” Hello World v1 for PSP v2.0 (w) 24/09/2005 by Groepaz/Hitmen”. After this happens i reboot my psp but version 2.0 is still there. I’m trying to downgrade to 1.50 but all my attempts failed. Please help.
same as 250
i have downloaded each mphdowngrader that is supplied at the top of this page but when i go to copy the overflow.tif file my nortons antivirus thingy comes up and says that nortons antivirus has found a virus and deleted it and its from the overflow.tif file and it says its called Trojan.PSPBrick. Does anyone know where i can download a downgrader without this virus?
it wont ley me open the tif file so nothing happens. help?
it wont ley me open the tif file so nothing happens. help?
Yep Works, but I was told there is a hack that allows the 1.50 to be able to play Version 2 games Originals, will this one do it? and where does the bin files gaem images go?
It worked – you beauties!
I shat myself, but am really happy I went through with it.
Took everything off it first, and didnt risk the battery pull thing…but hey…thanks dudes
(uk 1003)
Suppose I have a 1.51 brand new PSP. Any chance of running homebrew? From 2.0 to 1.5 it is clear, but has anyone tried to do it from 1.51 to 2.0 and then from 2.0 to 1.5?
It seems dangerous to me… dont know what to do. Maybe I ll risk.
Can Someone help a thick person So can i downgrade my v2.01 to 1.50
Can Someone help a thick person So can i downgrade my v2.01 to 1.50
TO ANYONE WHO CANNOT GET THE BLACK SCREEN AND WHO’S PSP FREEZES AT THE PHOTO MENU.
MAKE SURE YOU HAVE THE h.bin AND index.dat FILES IN THE ROOT FOLDER (THE SAME PLACE AS THE ‘PSP’ FOLDER.
THIS WORKED FOR ME FIRST TIME WHEN I PUT THOSE FILES IN.
Is there a downgrader for version 2.5?
I have the same problem. Please give a solution to this
whats the point in wrecking your psp? its pointless and stupid. you spend about
i cnt figureout wat im doin wrong? wereis the root of the memory stick and i cnt see any file called mso:// or wateva its called. I go on2 the photo part and it freezes but no blank screen wit texts plez email me thnx
I have updated/downgraded a few times already with no problems. But then I deleted the downgrader files and Update 1.50 off my memory card because I needed the space. Then when I went to update to 2.0 to play GTA there was no text at all during the install screen. Luckily I remembered what to press to get the update installing (right, down, then x). Why did this happen??? I’m scared to do any downgrade/upgrade again. Please help. Thanks
MY PSP DOESNT DOWNGRADE IT KEEPS ON 2.00 VERSION . i FOLLOWED ALL THE STEPS BUT NOTHING WORKED. I NEED HELP!!!!!!!!!!!!!!!!
If anyone heres of a downgrader or homebrew apps/games for ver. 2.5 then please email me at raf_shc@yahoo.co.uk
Does anybody know why the fastloader initializes when you select a game and then does nothing more than that, its really starting to get annoying
my psp keeps freezing when i click photo from the home screen and then shutting off
well i tried this and the overflow thing came up as a corrupted data and i have no clue what to do about that so i jus kinda gave up e-mail me with some help id like to downgrade my psp blackmombaa@gmail.com
Unfortunately, the link is for the japanese version of the 1.5 firmware. You wont be able to play US UMD videos because of the region coding. It also gives you problems when you try to upgrade back to 2.0
is anyone currently trying a downgradeable option for those of us who retardedly updated to 2.5 and need to get to 1.5?
yes it works.
but need help i downgraded my psp to 1.5 but i can not play the games i bought from the shops cos it say i need to upgrade again . do i have to upgrade again just to play these games ????????
Can i get the web browser in my psp 1.5 version?