How to patch PS1 ISO's with ASM codes?

[Mezmorize]

Hmm, is it really that simple?
I actually went to that location before but it don't show any of the hex sequence there, is that normal?



Above is an image of the hex editor at the address 0x40ffc I see a byte of 0x38 which isn't in the replaced line of coding (3c028007), or in the above (80040ff8) or below (80041000) lines.

[lee4]

just remove the 8 from 80040ffc like so 00040ffc, inject your code into the game elf (SCUS_942.28)

[Mezmorize]

I've recently created my very first PS1 ASM code, and would like to patch it into the ISO; but don't know how to locate the hex sequence inside the ISO. Is there any type of tool to aid in doing this? So far I've attempted with Hex Workshop, and ps2dis (first time using ps2dis).

Here's what I've done so far to lead up to this:
1. Used ImgBurn to make a backup of the 'Greatest Hits' version of Spyro The Dragon.

2. Used No$psx for the first time and used the Infinite Health RAM code (80078BBC 0003) to create this code
Infinite Health (ASM)
80040ffc 0000
80040ffe 0000

3. Booted Codebreaker with pSX v1.13 to successfully test the cheat.

And that's as far as I got.
I take it you need to search for the hex sequence backwards, since searching for 3c028007 brings no results, but searching for 0780023c does.

Here's the debugger image of the line of code I replaced with zero's:
http://oi39.tinypic.com/23ts1o7.jpg


80040ffc 3c028007 <-Original
80040ffc 00000000 <-New

I'm guessing the file that needs to be hacked on the ISO is 'SCUS_942.28', but 0x65FFF is as large as the file is, so there's no way 80040ffc is the actual address.

Any help would be much appreciated!