Step 1 : Download Aldo's latest PS3 Cheats Editor.
Step 2 : Click the PS3 LOGO.
Step 3 : Select Download Latest Database from gingerbread's repository of Cheats
Step 3 : You are done!

For folks who still can't get this working. Here is another approach. It is slightly different and there are couple more steps but it works.
Step 1 : Install bdRESET2.pkg. It is included in your MM zip.
Step 2 : Start bdRESET2 it will start and does its work and will exit back to xmb. What bdRESET2 does it will reset path redirections. Will prevent black screen and freeze.
Step 3 : Start MM with your Disc [Example : Heavy Rain]. Say you select Castlevania. MM will exit and your Disc icon will be Castlevania.
Step 4 : Start Code Unique 2.3, select Castlevania, press [SQUARE] and in cheat menu, press [CIRCLE] to enable your desired cheat and press Start. Code Unique will exit back to xmb.
Step 5 : If your Disc icon is your disc's games in this case Heavy Rain, Start bdRESET2 and does its work and will exit back to xmb.
Step 6 : Start MM again, select Castlevania. MM will exit and your Disc icon will be Castlevania.
Step 7 : Start Code Unique 2.3, select Castlevania, press [SQUARE] and in cheat menu, press [CIRCLE] to enable your desired cheats and press Start. Code Unique will exit back to xmb. This time the disc should be Castlevania.
Step 8 : Start the game. The cheats should be enabled.

Q: What is a Joker Command?
A: It is a code whose address is a position in RAM, that tells when a button on the controller is pressed.
Q: Does everygame have a Joker Command?
Yes, every game has a Joker Command, but some are non-normal and non-reverse joker commands.
Q: What does a Joker Command do?
A: It is used to avoid lockups during the intros or varios places in the game, or when you only want to activate codes at a certain time and not constantly have the effect of the code. It's purpose is to activate codes at the touch of a button.
Q: Can you activate all codes from a Joker Command?
A: Yes. All you have to do, is put in the Joker Command Code in the Master Code Section, otherwise, it will just turn on the code that is below it.
Note : These Q&A are from PS1 & PS2 era, but they give you an rough idea.

Whatever your game, download CMP Auto Tools 6.3. Put that in C:CMPAUTOTOOLS6.3.
Put the game's files in C:CMPAUTOTOOLS6.3GamesSource.
With a window for both C:CMPAUTOTOOLS6.3 and C:CMPAUTOTOOLS6.3GamesSource open, click and drag your game on the batch file called SELF2ELF2TXT.bat. You aren't going to be finding or making codes on your own so when the batch file asks if you want to generate the text file of the game's, so just pick choice 2 to skip it when it asks. It should only take a few seconds or less and the window will disappear.
There will now be an elf file of the game in the directory C:CMPAUTOTOOLS6.3MAINELFS. Open that file with a hex editor, like HxD which comes with CMP Auto Tools 6.3.
You have these for codes:
00002000 016A8F78 60000000
00002000 016A4360 7D3F0214
Remove the first 8 digits because they are a code type for CodeUnique. You have this:
016A8F78 60000000
016A4360 7D3F0214
CodeUnique codes have things 00010000 higher in memory, so just subtract that and get:
01698F78 60000000
01694360 7D3F0214
In HxD with the game's elf file open, press CTRL+G for the address jump box to appear. Type in address 01698F78 and press enter. Change the value to 60000000. That's one code down. Press CTRL+G again and go to address 01694360 and change the value to 7D3F0214. Save the changes and exit out of HxD.
With both of the windows open that you used to drag the game's files onto SELF2ELF2TXT.bat, drag them over whichever one had 'DnD' in the title of the batch folder. It will ask whether you are on 3.55 or lower, or on the 4.30 CFW. Pick your choice. HxD will pop up with the game's SFO file open. Go down to where you will find 'DG' in it somewhere and change it depending on how you want it. I always change it to 'GD'. Go to the very bottom where it has the game name and B??S##### with 4 capital letters and 5 numbers after it. After it should be some number with a decimal point like 1.00 or 1.01. Whatever it is, change it to a higher number. Save and exit. The batch file will continue on and should create a package in the C:CMPAUTOTOOLS6.3GamesSource directory. Place that on a pen drive, turn on the PS3, and run the package. Now those codes will be in effect every time you play until you either delete the game data or replace it with a different package.

No. It will not work even if you were to resign it using various resigning tools. It has to be re-written from scratch since it use the old MultiMAN code. Only oct0xor has the source code. Unless another PS3 homebrew developer recreate a similar application that uses the database to inject the codes into PS3's memory.

The Recommended CFW is Rebug 3.55.3 REX Edition.
I have not tested with Rogero 3.55 V3.7. If more users share their experience with other CFW, I will update this section.

1. Download, install & run PS3 Cheats Editor 2.4.1
2. Select a game from the database
3. Select the cheats that you want to apply (use Ctrl+click to select multiple cheats)
4. Press Ctrl+E to select the EBOOT.BIN of the game to be patched (make sure that it is the same version)
5. Press Ctrl+P to apply the selected cheats
6. Press Ctrl+J to save the patched EBOOT.ELF as EBOOT.BIN
7. Copy the EBOOT.BIN to the USRDIR folder (if it is a retail eboot) or make a PKG if it is a PSN game or update EBOOT
Options for 4, 5 & 6 are available in the context menu found at the bottom-right of the window (hover the mouse over the Patch ELF button)

This Info was provided by @haxxxen
SET OGP=Original Pattern
SET COP=Code Pattern
Example :
On this example, you can see that only the first set gets changed, so you note the offset of the first different byte (0198C790) and add 10000 (Address).
Now, you can convert the information into this format.
00002000 'offset of the first changed byte' (here 0199C790) 'changed value' (here 60000000) so the code goes:
00002000 0199C79060000000
Note : This may not work for all Pattern, but it is a start.
More Info :

Usually 80% - 90% of the time, the offsets are updated correctly by the authors of the code to work with CodeUnique. But in some cases. some authors like @bungholio , releases cheats/code without updating or adding them. Usually the authors themselves will an info to add them manually. Tip: One way to check if the codes need update, Press F1 to open Info Window. Compare Values and read instruction from authors.
In such cases, here is how to update/add 00010000 to the offset.
1. Right-click on the cheat, Update Offsets or F7 to open Dialog Box.
2. Enter the new difference in *hexadecimal*. e.g. 10000 or 0x10000. Enter 0x10000 to add 00010000 the offset. Press Ok, after that. If you need to substract 10000, enter: -10000