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Oct 6 / kkrizka

How To Apply the PSP 3.71 M33-2 Patch

Just a couple of days ago I have announced that the PSP custom firmware installation guide was updated to version 3.71 M33-2. However, thanks to HackerYami, I realized that there is a problem with the installation package. The package only included a patch for the custom firmware, so you already need to be running 3.71 M33 on your PSP. The following tutorial goes over the installation of the patch, after you have installed the 3.71M33 firmware upgrade following my guide.


  • A fat PSP with firmware version 3.71 M33
  • At least a memory stick with 128 MB of free space
  • Fully charged battery (or just leave it plugged in the power)
  • M33 update package that includes the 3.71 M33-2 patch and the 1.50 kernel patch.
  • Patience to follow this guide step by step

Install 3.71 M33-2

  1. Connect your PSP to the computer via a USB cable.
  2. Copy all files on the memory stick to a hard drive. This is a backup just in case something evil happens, even if it’s unlikely.
  3. Copy the UPDATE folder (found in PSP/GAME folder in the installation package) to the PSP/GAME folder on your PSP.
  4. Disconnect your PSP from the computer
  5. Navigate to the games section of the XMB on your PSP and select the Memory Stick tab
  6. Run the application called “3.71 M33-2”
  7. Press X to continue
  8. You now have 3.71 M33-2 on your PSP!

If you come across any problems with this tutorial, I suggest you visit the urPSP forums and post your query there.


Leave a comment
  1. Las Vegas Guy / Oct 6 2007

    Nice catch. I just sent this to my friend so he can upgrade his PSP.

  2. HackerYami / Oct 9 2007


  3. fossilblue / Oct 12 2007

    Can we use this patch for PSP slim and lite?

  4. XpanD on PSP / Oct 12 2007

    I’d advise you to go and upgrade (always do some research first!).

    M33 firms tend to just give you an error, stopping the installation.

  5. tero / Oct 12 2007

    when i copied the update folder to my psp and looked under the memory stick in the games section it just said update version 3.71 not 3.71m33-2. is that the same thing?

  6. Marcos / Oct 23 2007

    I was wondering if there is any chances of upgrading and messing my PSP, making it into a brick. I have FW 3.03 Also, can i still play all my ISO games once i updated?

  7. XpanD / Oct 24 2007

    Ofcourse there’s a risk, there always is…

    However, if you follow this guide to the dot, you do not have that much risk involved. Especially if you know someone with a modified Pandora’s battery.

    Just be sure you’re on 3.52 M33 with the #3 or #4 patch installed before even attempting the installation of 3.71 M33.

    After installing 3.71 M33, you can go and follow this (awesome) guide.

  8. XpanD / Oct 24 2007

    Oh, and if you’re on the official 3.03 firmware, you’ll need to downgrade to 1.50 first, before being able to upgrade.

    PS. Karol, sorry for the double reply.

  9. nefty / Oct 28 2007

    when i copied the update folder to my psp and looked under the memory stick in the games section it just said update version 3.71 not 3.71m33-2. is that the same thing?email me plzzz!!!

  10. purekaoz / Oct 31 2007

    if you’ve actually read the guide,it says u need a firmware of 3.71M33 first. So before even upgrading from 3.03 or others you need to upgrade to 3.71M33 first to apply the 3.71M33-2 patch.

  11. XpanD / Nov 1 2007

    Assuming he/she has the actual 3.71M33 version installed, he can safely run the program.

    So… If you’re reading this, nefty, just try to run it. It’ll just show an error if it is already installed. You’ll always see a message where you can confirm, and you can see what the update you’re running is gonna do, so you should be safe even without an error.

  12. Charly / Nov 12 2007

    You guys deserve a medal!!!

  13. pspMAN / Nov 17 2007

    I have already upgraded to 3.71 m33 but when i try installing the patch i get:

    “The system software of your PSP
    system is version 3.71.
    There is no need to update”

    I have followed the direction to the dot but i don’t understand what the problem is. Can anybody help me.

  14. DoneDeal / Nov 24 2007

    I have a PSP Slim with the PSP 3.71 firmware installed on it. I recently downloaded PSP 3.71 M33 update 2, but when trying to install the upgrade I get an “The game could not be started. (80020148)”.

    My questions is, what am I doing wrong? Do i need to have a PSP Fat, and mod my M-card before I can get the 3.71 M33 Update 2 to work? And if so, what is another alternative, because I already sold my PSP Fat.

  15. XpanD / Nov 24 2007

    Well… First of all, M33 firmwares are custom modified firmwares.

    You can’t upgrade directly from the original 3.71 to 3.7 M33-2 (or any other custom firmware for that matter).

    The error you’re getting means you’re trying to run code that Sony hasn’t approved themselves.

    In order to actually get your PSP Slim to a custom firmware, you’ll need to use a modified battery and a modified memory stick (known as the Pandora’s battery combo).

    In order to get a battery and memory stick modified this way you’ll need to have an old fat PSP which can run homebrew (it should be at firmware 1.50 or at a custom firmware, other firmwares require downgrading to 1.50 first).

  16. MonochromeNight / Jan 29 2008

    I think that the actual link to the M33 update package is:

    To the author of the site: please correct the URL. Thanks!

  17. Stephan / Feb 1 2008

    Hey, I’m new to all this psp custom stuff so please help me.
    I’ve got a PSP slim and lite which has 3.80 offical sony firmware. How do I get 3.71 M33.

    I’ve copied the update and did everything but when I run the update it say your PSP version is 3.80. There is no need to upadte.


    Thank you very much!

  18. Donedeal / Feb 2 2008

    OK stephan, I once was in your shoes last year. I’ll tell you what I did. Very simple. First you are going to need to spend a little money, about $40.00 on a Datel Battery. With this you don’t need need to have a Phat Battery. Once you have the Datel Battery, then you need to get your hands on PSP magic stick files, its about 185 MB file that if you look hard enough you can find it “online somewhere”.
    But once you have all of those things you will load the PSP magic stick files, which are really files that are created with the FAt PSP, but you will load those to your memmory stick, then once your Datel is fully charged you will put in the battery, with that battery it will put your PSP into service mode, and once in service mode the BIOS will recognise the PSP magic stick files and begin downgrading your PSP to an ealier Firmware version hopefully 1.50 if you find the right files. The files that I have were setup so that it install 1.50 and then during the installation also then upgrades you to 3.71 M33-2. So, if you have any questions, halla at me.

  19. Dennis A / Jun 20 2008

    Hi Karol,I have a fat PSP with 3.71 M33-2 installed with 4GB memory stick. All the other games I play seem okay except for Justice League which hangs in loading after the team-up of flash and green lantern. My niece’s PSP also has the same situation. I browsed the net and JLA has no reports for bugs or anything like that. Do you have a suggestion. Thanks man!

  20. lolz / Jul 1 2008

    umm my psp is version 3.71 not version 3.71 m33 so how can i download version 3.71 m33 from my version whic is 3.71 not 3.71 m33

  21. Brandon / Aug 16 2008

    ok, first of all i started with putting a ps1 game on my psp but then i figured out that i needed custom firmware. The update thing in my game memory was corrupted. so, i just did update but the new version is out now (4.50) and i want to know if 4.50 can be changed to m33 so i can play ps1 games on my psp. plz help me i went throught all the steps in putting a ps1 game on my psp and now the new version is out and i can find anything that tell me how to get custom firmware for 4.50. Please e-mail me back at thank you

  22. irishbloke / Oct 14 2008

    Awesome guide,worked perfect. I Upgraded from 3.52 m33-4.

  23. Hayden / Jan 21 2009

    My version is 4.01 which is higher than the 3.71 one. When I go to open it, it says that there is no need to update. Is there a way which I can downgrade it without this error coming up?

  24. speedyspeeder707 / Jan 14 2010

    no im real new at this so i have question

    i bought a pspslim from a pawn shop and it has v 3.71 m33-2 already installed and has program called NesterJ NES emulator 1.11RM

    and SNES9XTYL0.4.2mecm already installed. is this already set up to play iso games i download off web?

  25. donedeal83 / Jan 16 2010

    Yes, it is. You need to do some updating though, because there are certain games that require a certain upgraded revision of firmware. Currently I believe the latest if 5.50 Gen-B firmware, which you need to install Gen-A first and then upgrade to B, but just follow the forums online they’ll guide you. You should be able to jump into the 5’s as far as updates are concerned, and then do upgrades one step at a time.

  26. Bob / May 3 2010

    So my friend already has 3.71 m33-2 on his psp and he has a pandora battery. and since i have a diff CFW on my psp, i don’t know if everything works the same way. so dumb question: do i just put the iso and cso files to play the games downloaded? like cso and iso files?

  27. Michael / Apr 20 2011

    My cousin just gave my 5 year old son his old Fat PSP with Vr3.71 M33-2 on it. We have just bought my son the new Star Wars III (PSP) game but it will not play. It ask to update the firmware. When I tried to update, it says that I have the latest version. Can anyone please help, my son really wants to play his Star Wars game? I have a PS3 at home and not impress with the PSP.

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  1. PSP Custom Firmware 3.71 M33 Guide | Karol Krizka
  2. Custom Firmware Extender v1.8 Released | Karol Krizka
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