3.52 M33 by M33=Dark_AleX
===================Requirements
-------------- In order to install 3.52 M33 Firmware you will need the following:
Precautions/Suggestions before you start
--------------------------------------------
- Ensure the memory stick used for the upgrade/downgrade process is in good shape. This means it's got no bad sectors that may result in failed CRC checksums for the files contained in it.
- Normally if your Memory Stick is legitimate you should not have any problems. Many people have experienced semibricks / bricks due to cheap fake and unreliable memory sticks sold on eBay. As a suggestion I recommend you either use the original 1GB memory card bundled originally with your PSP or find out whether your memory stick is legitimate or not before attempting the process.
- A good practice would be formatting the Memory Stick prior to the downgrade (Remember to back your important files up before you do that) and use any error-checking utility to scan the Memory Stick for failures.
- Alternatively you can use a CRC checksum utility (SFV, MD5SUM...) to verify that the data copied onto your memory stick is consistent with the original.
- Charge your battery to its maximum capacity in advance and leave the PSP plugged to the mains during the upgrade/downgrade process.
- During the upgrade/downgrade process, once the files have started being copied to the flash memory you MUST not be reboot your PSP manually, or turn it off, or the remove the Memory Stick until the flashing process has finished, or otherwise your PSP will end up bricked.
Installation
------------IMPORTANT NOTE: Steps No. 4 and 14 are ONLY for users installing the 3.52 M33 from a 1.50 PSP. Those installing it from a PSP running on a CFW already MUST skip those steps as thery are irrelevant in that case.
1.- Download the 3.52 M33 by M33=Dark_AleX from the above link. Uncompress the contents of the downloaded "
3.52M33.rar" file into a handy location of your HD.
2.- Connect your PSP to your PC via USB cable and enable the USB Mode on your PSP.
3.- From your Operative System, go to the directory
:/PSP/GAME located in your memory stick.
4.- Remember that this step is ONLY required if you are trying to install the CFW from a 1.50 PSP. If you are installing from another CFW you should skip this step.
Locate the uncompressed folders
kxploitpatcher and
kxploitpatcher% in your HD (They´re within a folder called
1.50Only). Copy such folders plus the contents into the folder
:/PSP/GAME of your Memory Stick. You should have
:/PSP/GAME/kxploitpatcher/ and
:/PSP/GAME/kxploitpatcher%/5.- Locate the uncompressed
M33CREATOR folder in your HD. Copy such folder plus its contents into the folder
:/PSP/GAME/ (if you are installing from a 1.50 PSP) or into
:/PSP/GAME150/ (if you are installing from another CFW) of your Memory Stick. You should have something like
:/PSP/GAME/M33CREATOR/ (for a 1.50 PSP) or
:/PSP/GAME150/M33CREATOR/ (for a CFW PSP).
6.- Download the 1.50 Official SONY Update File from the download link above. Make sure you select a handy location in your Hard Disk where you can find easily it later on, i.e. Your Windows Desktop. The Update EBOOT.PBP file will be packed in ZIP Format and you might need some additional software to uncompress the file (for instance WinZip). Uncompress the ZIP file, and you should en up with a uncompressed file named
EBOOT.PBP. This is the uncompressed Firmware Update file. Keep the file in a handy location easy to find in your HD.
7.- Rename the file
EBOOT.PBP into
150.PBP.
8.- Copy the file
150.PBP from your HD into the folder
:/PSP/GAME/M33CREATOR/ (if you are installing from a 1.50 PSP) or into
:/PSP/GAME150/M33CREATOR/ (if you are installing from another CFW) of your Memory Stick.
9.- Download the 3.52 Official SONY Update File from the download link above. Make sure you select a handy location in your Hard Disk where you can find easily it later on, i.e. Your Windows Desktop. The Update EBOOT.PBP file will be packed in RAR Format and you might need some additional software to uncompress the file (for instance WinRAR). Uncompress the RAR file, and you should en up with a uncompressed file named
EBOOT.PBP. This is the uncompressed Firmware Update file. Keep the file in a handy location easy to find in your HD.
10.- Rename the file
EBOOT.PBP into
352.PBP.
11.- Copy the file
352.PBP from your HD into the folder
:/PSP/GAME/M33CREATOR/ (if you are installing from a 1.50 PSP) or into
:/PSP/GAME150/M33CREATOR (if you are installing from another CFW) of your Memory Stick.
12.- Disable the USB Mode safely and disconnect the PSP from the PC.
13.- In the PSP's XMB Menu, go to "Game" -> "Memory Stick"
14.- Remember that this step is ONLY required if you are trying to install the CFW from a 1.50 PSP. If you are installing from another CFW you should skip this step.
Highlight the "
KXploit permanent Patcher" and press the X button to execute the program. It will ask for confirmation. Once finished it will take you back to the XMB, so go to "Game" -> "Memory Stick" again.
15.- Highlight the "
3.52 M33 CREATOR" and press the X button to execute the program. Once finished it will take you back to the XMB.
16.- Go to "Game" -> "Memory Stick" again.
17.- Highlight the "
3.52 M33UPDATE" and press the X button to execute this program which will require at least 78% of battery charge. It´ll display a disclaimer and ask you to press the X button to accept and continue. Once finished press X to shut down.
18.- Restart your PSP. Check your PSP Settigs Menu (Settings -> System Settings -> System Information). You should be now in 3.52 M33
Installing the latest bugfix patch
----------------------------------Currently the latest patch is the
UPDATE #4. Your PSP must be running 3.52 M33 already prior to the installation of this patch. These update patches usually correct bugs identified by users, hence it´s strongly recommended to apply them.
1.- Download the
UPDATE #4. This patch is cumulative, meaning that includes all the previous ones already.
2.- Uncompress the contents of the "
M33-1234.rar" file into a handy location your HD. Browse the uncompressed contents in your HD, and you will see a folder called
M33UPDATE4.
3.- Connect your PSP to your PC via USB cable and enable the USB Mode on your PSP.
4.- From your Operative System, go to the directory
:/PSP/GAME150/ located in your memory stick.
5.- Copy the
M33UPDATE4 folder and its contents from your HD, into the folder
:/PSP/GAME150/ of your Memory Stick. You should have something like this
:/PSP/GAME150/M33UPDATE4/6.- Disable the USB Mode safely and disconnect the PSP from the PC.
7.- In the PSP's XMB Menu, goto "Game" -> "Memory Stick"
8.- Highlight the M33 Updater and press X button to execute the program.
9.- Press X, and the Update will be installed.
10.- Check your PSP Settigs Menu (Settings -> System Settings -> System Information). You should be now in 3.52 M33-4
Basically these are the Original CFW / UPDATE Instructions from the ReadMe.txt with a few additions / changes to make it more understandable.
If you have read the instructions but you are still having trouble to get the CFW installed working, we suggest that you reply to this topic with the question(s) that you may have rather than starting a new topic/thread instead. We'll try to help

.
Hopefully this guide will stop unnecessary threads from people asking the same questions again and again.
It goes without saying that any replies asking or discussing about ISO capabilities of any sort will be automatically deleted. O:-)
Once you´re on 3.52 M33-4 you will be able to install
3.71 M33 CFW but bear in mind that PiKey is not compatible yet with 3.71 M33, so if you´re frequent a PiKey user we suggest to stick to the 3.52 M33-4 CFW in the meantime.