Happy New year everybody!

I wanted to test if I could develop infinite lives Cheat for SMB1. So I dissassembled SMB1 rom with TRaCER. Then I studied the code for few hours(I'm a newbie). I thought the amount of lives was substracted with SBC.So I listed every SBC $01 and SBC #$01 and one at a time replaced them as SBC $00 or #$00.

That resulted few Graphic bugs, but the amount 0f lives was still dropping at every death...

Then I tested GG code that gives infinite lives(SXIOPO), that worked fine.
Nesticle said the code patches address 91D9 with AD.

In both of my dissassemblations(groovy word)(without ines header and with)address 91D9 was information or "???".

Where do this patch really belong to?
I don't really care about the code, but I want to know how is it done.

I'd really appereciate if somebody could help me with this topic.

And btw I found this thing on SMB's code:

00/8057: 4C 57 80 JMP $8057

What's the purpose of this one?
Is it waiting for some interrupt or something?

I looked at it in FCEU's debugger. The code at $91D9 is "DEC $075A", which decreases the byte by one. Same result as SBC #1, but a simpler method. The game genie code changes that to "LDA $075A", $075A is unchanged in that case.

About the infinite JMP loop, you guessed it. It just sits there during the idle time, while all the code is ran from the NMI routine.

Thank you :)