I was looking at pictures of the x ray 3 modchip that a lot of people use for recovering a bad TSOP flash, and the modchip looks very simple. I only see a 32 pin PLCC socket and a SST PLCC chip, and since there are 33 points that seems about right. Could I build something like this?

It sounds like a cheapmod but the SST 49LF020 is very difficult to find.

I already have at least 20 SST 49LF020 chips and PLCC sockets so that's not really the problem. By the way, what bios would I flash to it if I did make it?

Any 256Kb sized bios appropriate to your xbox version - examples are EvoX M8+ 1.6 for 1.6 or IND-Bios 5003 for 1.0-1.5. For LBA48, .6 or .67 depending if you want F or F/G drives.

Hang on a minute - is this a 29-wire modchip?

Yes, this is going to be a 29 wire modchip

The cheapmod is a lpc installed homebrew chip and the schematic was available. I'm not familiar with 29 wire modchips and don't know if the schematics are available.

EDIT: Found a diagram but no idea what bios to use. How does a 29-wire modchip work?

The problem is that schematic shows how to create a 29 wire modchip using a flashrom chip and not a 32 pin PLCC chip. Are there any other schematics floating around? I my just break down and buy an Xray 3 if I can't get this to work.

simply find the chip that you wish to use be that flashrom or eeprom and then simply go to manufactures website and get pin outs on the plcc and packed featured in that diagram and connect them to the correct pins. simple really.

cheers

Indeed, most of the flashrom chips are produced in different packages. If you look up the datasheet of the manufacturer, it might show you the possible packages and the function of each chip pin.

The 29 wire modchips simply replaces the original Tsop flash on the mobo. As modern modchips use the LPC bus for their connection to the mobo, the 29 wire modchips simply use adress and data lines.

Connecting 29 wires to the mobo correctly is not an easy job. That's why they started to use the LPC bus.

There is an SST flashrom chip that has the LPC interface embedded in the chip. That's the one that is used for a cheapmod.

If you boot from the LPC bus, there is no way anymore to access the on board flash. So, for that reason you need a 29 wire modchip if you bricked your mobo due to a bad tsop flash.

regards.

Hey Joe, Where did you find those 49LF020A's?

I too am looking to make a few modchips.

BTW, the SST49LF020A is an LPC flash. You would probably have better luck using the type of chip in the diagram that idotsfan posted. But from what I gathered, you can only use the homebrew 29 wire modchip on a version 1.0/1.1 xbox.