Do I need to install P5EX's patch?

Short answer: Yes

Why? This is so that the mod can work properly. But to be more precise, running P5EX patches without P5EX installed, will softlock the game.

How do I install P5EX's patches?

Before we can do that, we need to locate the patch file and find it's PPU-hash.

You don't have to know what a PPU-hash is: the important part is that we need to find it and compare it with P5's PPU-hash.

You can read more in how to find P5EX's PPU hash here:

Finding P5EX's patch's PPU-hash

Why is this important?

It’s to ensure that it’s using the right version of the game. Since some games can have regional differences, this can affect the games' code. While not too critical in most cases, it’s best that the two hashes in the patch.yml are the same as the PPU hash in your copy of P5 to ensure that the game patches work smoothly.

If you know how to find the PPU hash of P5 you can jump directly to Comparing hashes.

Comparing Hashes