Here’s a member sumbitted video showing that PS3 Custom Boot logos and sound are still possible even on the later locked down firmwares. The video shows a PS3 Slim console on FW 4.00 booting with a custom boot sound and custom boot logo.
The process for achieving this remains the same as in the older firmware revisions with a few minor changes to the tools required.
First step would be you mount the PS3 flash memory using any of the available tools for this. Even the old original dev_blind pkg is still able to do this. You would next need to use the latest PS3 Cold Boot creator app (windows only at this time) to compile together your required transparent logo and both version of the cold boot sound. To be clear on this probably only one of the boot sounds will be used by your PS3 depending on your audio setup. The two files of interest are coldboot_multi.ac3 and coldboot_stereo.ac3. If you are not using a multi channel surround sound system then the PS3 will use the coldboot_stereo.ac3 file so you may use any stereo mp3 to plug into the generator. Please select the box to ‘copy stereo to multi’. If you do not select this the compiler will also require you to include either a multi channel wav, mp3 or ac3 file which will be output when the PS3 boots in multi channel surround sound mode. The length of your boot sound is limited to appoximatly 8 seconds however some lengths appear to cause the sound not to be played correctly on boot. If you experience problems with the start of the ps3 boot sound being missed then you should go back and experiment with sounds of a slightly longer or shorter length. Adding a few milliseconds to the sound may in some cases be all that is required for you to do.
Once you have your cold boot compiled by the tool you will have three files in the folder.
You must now start the PS3 and run dev_blind to mount the flash memory as an accessible drive. Now start the FTP server of your choice on the PS3 such as OpenFTP or BlackBoxFTP. Back on the PC now run your FTP client (Filezilla recommended) and enter the IP of your PS3) and connect with no username and password entered (annonymous mode).
Before continuing please understand you are about to change files relating to the PS3 operating system which is stored in its flash memory. Only change the files mentioned here changing any other files can and probably will brick your console with no way of repair!
So understanding that…
Browse to the drive dev_blind then to the folder vsh. Inside that open the folder Resources. Copy the three files from the compiler folder of your pc to the folder on the ps3. Reboot PS3 and you have your custom cold boot!
Of course before you can run homebrew on the PS3 you will need a PS3 Jailbreak for the latest firmware.