	Cheapmod	Need stuff Designing? I am a consultant, designing hardware and software, based in the UK at www.addintelligence.com Also, SCO vs Linux related stuff here
	by andy@warmcat.com
If you can get hold of the $2.50 SST49LF020, you can build an alternative BIOS for $4.

Note	This project has been built and tested, and works fine.

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The Cheapmod Project

Scope

Cheapmod is an SST LPC flash mounted on a standard LPC header.

Every day I get a handful of emails asking me which flash chips can be used. The answer is: SST49LF020 ONLY. Not even the -A version of the same chip will work. Please read the CheapLPC page for more informtion.

Overview

Bottom view, all of the pins are pointing up at you in this diagram

Principles

Only 3.3V is used, 5V is not used from the LPC connector

Programmable via CheapLPC - you will have to build CheapLPC if you want to use this design

Cheap, cheerful, but built carefully will work great.

Implementation

Minimal mod with detailed fitting instructions

On the day of the recent price reduction I went and purchased a second XBox - at GBP132 + VAT they are an amazing bargain as a generic XWindows Linux machine.

I took some photos as I modded it with Cheapmod. I decided that I would be the cheapest possible kind of git this time, and so I removed the 0.1" socket, and am soldering directly to the LPC connector.

Before you start, you need to have a working CheapLPC and to have programmed an SST 49LF020.

First, here is the PLC C socket with the unused pins snipped off, and several pins straegically bent over to simplify soldering

Next we solder all the pins together, tin all of the pins that will be taking a wire ('tinning' means to wet the pins with solder so they can later be easily soldered to the wire), and in the photo do the 0V wire, which is the only one that needs two hops.

Next we add the 3.3V wire. Note how we placed the wire in the middle of a gap between to sets of bent pins, and filled the gap in with solder so both sides are all connected up.

Okay, after that, all the rest of the wires are pretty simple. You will have noticed the black stuff I add on top of the soldered joints. This is heatshrink tubing. After soldering the wire, I snip a short length of this off and place it over the joint. Then I heat it with the soldering iron, the special plastic shrinks to conform to the joint. This relieves strain from moving wires, and makes sure no loose strands of wire bust out and short to things they shouldn't. And, it soothes my conscience about performing these outragous bodges.

Boy this picture is out of focus. What it intends to show is at the top, stripped wire that is untinned. Instead it shows the astounding difference between one blurry white/silver thing and another one. At the bottom, the same deal that has been well tinned with solder. It becomes a solid unit, with no wild hairs of wire busting out of it. It should not be heated up so much that the plastic insulation shrinks back or becomes burnt.

So, our mod is done, now it needs to be fitted.

Alright. Here is the place on the Motherboard that you will be becoming familar with, the LPC connector.

The guy with the sticker next to it is the motherboard flash.

We have two kinds of job in this area. First, we have to solder the tinned wires into the LPC connector. Second, we need to short one of the vias to 0V, thus enabling LPC for boot.

Okay, here is 0V soldered in. How can you solder these wires without removing the motherboard?
OMG OMG!!

Relax, with a little practice and knowledge, its easy.

First heat the pad from the side. Microsoft kindly prepared it with a nice load of solder, you won't need any extra. When the solder is molten, apply the tinned wire rapidly into the hole and remove the iron. Done.

Here is the whole thing suddenly done, jussli'that.

Notice the patch wire from a via to the south side of C7C4. This is forcing D0 of the motherboard flash to 0V and is necessary to get the LPC mod booted from.

I had to gently scrape the via surface with a scalpel in order to be able to get the solder to adhere to it. Do NOT use excessive force here, the via and/or tracking will bust off and you will be in deep dodo.

That's it, good luck!

Viperman's PCBs

Viperman from Xboxhacker has also made some PCB images for cheapmod. I have not tested them and am merely passing them on.

Viperman's Cheapmod PCB PDF
Viperman's Cheapmod PCB Gerbers

Max la Menace's Matrix programmer repurposing

Our French friend Max la Menace was irritated by the nonstandard connector on his Matrix programmer (which is simply a CheapLPC with a battery holder). He sat down with a Multimeter and sent us the following diagram about its connector:

This is very clear and useful, then, it means that you can program Cheapmods using the Matrix programmer by making a small adapter. Here is the correspondence between the named pins on Max's diagram, and the numbered LPC connector pins at the top of this page

LPC pin #	Matrix pin name
1	LCLK
2	Gnd
3	LFRAME
4	(key)
5	reset
7	Lad3
8	Lad2
9	3.3V
10	Lad1
11	Lad0

Now thanks to Max you can blow Cheapmods on your Matrix programmer. :-)

Cadfael's PCB and switch

Cadfael (cad.fael@laposte.net) has sent the following nice pictures in from France, with a note:

Andy,

For the beginning I want to say that all the benefits must be
sent to you for your wonderful tutorial on 'How build your
homebrew LPC mod' and to Viperman from Xboxhacker for is
modchip pcb. Many thanks to you.

I was just concern on an easy way to plug and remove my
modchip so I decided to use a pin header system to connect my
modchip on the motherboard.

This is just an extension to the tutorial mentioned before.

It worked for me and I just want to bring my very very little
stone to the scene.

The only drawback is that you have to completely remove the
motherboard to weld the pin header on the underside but it is
a far better solution than wires (and also I think than the
no solder pogo pins). It is stable, quick and easy to install,
the mod can be removed with ease and replaced in seconds. No
alignment, no setting up. The main benefit is that once your
pin header is fitted you NEVER need to solder ANY mod into
your XBOX ever again!

Note also that the v1.1 consoles LPC holes are not filled in
so it’s easier, just plug the header in and you're connected
within minutes.

For the patch wire, I chose to use the point 2 (GND) of the
LPC connector cause like that I had only one 'difficult' point
to weld on the motherboard instead of 2 (D0 and south side of
C7C4)

You can notice that I have also put a switch on the patch wire
so I can easily turn on/off my modchip and boot on MS original
bios or on my 'underground' one. Works fine too.

I used the PCB of Viperman (works fine) with a pin header
block and PLCC support for my chip.

After programming my chip I only have to plug my chip on the
motherboard.

I sent you some photos, I suppose that it should be enough
have a good idea of all the steps of my 'procedure'.

Best regards from a french guy.