As the topic states, I am working on a homebrew LPC modchip using the SST 49LF004B.
I could not find a diagram online so I gathered the required info myself and constructed my own diagram.
I don't have the chip here with me or I would test it myself.

I just need someone to concur that my diagram looks/is correct.

According to the data sheet on the chip:

The MODE pin must be held low to put the chip into LPC mode.
The CE# pin must be held low to enable the chip.
The WP# must be held high (low for write protect) to disable write protect to the data area of the chip.
The TBL# pin must be held high (low for write protect) to disable write protect for the boot block of the chip.

So, What do you guys think? Any input is good input.

I can't remember where I got this from, and it's a bit blurred, but it seems to confirm your wiring - but with loads more pins tied to 3.3v (LPC pin 9)

My electronics is really half-baked but isn't the SST 49LF004B a 4Mbit? Does the xbox have sufficient address lines for the chip since the tsop is only 1Mbit.
Or you plan to install SPDT switches to fool the xbox into thinking it is looking at one bank of 1Mbit at any one time?

By the way that's 8 banks of 512K in there - is that bigger than a X3's?

Yes, 4 Megabit (512k), not 4 Megabyte (4096k).


@heimdall

Yep, That's what I was looking for. Thanks man. I guess what I'll do is start with my diagram, and if I have any issues, I will use the diagram you've posted for a reference adding those extra hot lines one at a time till I get the xbox to boot.

The data sheet on the 49LF004B makes no mention of the GPI pins having to be tied high. That diagram you have is interesting. Altho, my chip and the chip in your diagram (49LF020-A) are slightly different. This will be a great project. Can't wait to get started.

You won't be able to use that chip for a cheapmod, you'll need to alter 2 bits in the data stream with a cpld and it's also software write protected so you need a special flasher to flash it in the xbox. I doubt I released any flasher for it.