How to recover a Digi Connect ME, WiME, EM, WiEM, & SP JTAG'less C module

Introduction
This document describes how to recover a Digi Connect ME, WiME, EM, WiEM, & SP JTAG'less C module (hereafter defined as a module) with a user defined image.

These modules however need to be the 'C' or Custom variant. They also need to be C modules without a JTAG interface. C modules with JTAG interfaces should use the NAFTPAPP example application to load the intended image instead of using this method. This procedure will not work on 'S' or standard modules. As a result, it will not work Integration Kits or with Development Kits running with S modules.

Background
The Digi Connect C JTAG modules are designed with development purposes in mind. The developer is expected to write their image (a.k.a. EOS, firmware, & application) with the JTAG C modules and then test it. When they have tested their modules to their satisfaction they will then want to deploy their image out to their JTAG'less C modules for manufactoring purposes. For whatever reason, sometimes images can be written wrong, become corrupted etc. This document gives the users a chance to recover their JTAG'less C modules.

This document is not a guaranteed fix however. Depending on why the module isn't booting will determine if this procedure can restore the module or not. Here is why.

When the boot loader on the module starts up it checks the image header (first 65 bytes) and does a Cycle Redundancy Check (CRC) on the image as a whole. If either of those things fail then the boot loader will attempt to find a DHCP server in order to recover an image. Now, if the the image doesn't work BUT has a valid image header AND passes it's CRC check, then this procedure can't occur, the unit still won't boot, and the module will need to be RMA'd.

Assumptions
It's assumed that the module is in a non-functioning state. It is also assumed that the reader has a C module with a development board. The reader is expected to be familiar with networking and computer related concepts. They are also expected to have a basic understanding about the Digi Connect module (install, setup, & configure).

As stated before, this document is intended for JTAG'less C modules.

Tools Needed
DHCP server – This will need to have the ability to set options 66 (name of TFTP server) and 67 (file to download).
TFTP server
Digi Connect module (C without JTAG) - ME, WiME, EM, WiEM, & SP
new image for module

Procedure
Setup a DHCP server
This must have the ability to define DHCP options 66 (IP address TFTP server) and 67 (file to download). This must also be setup on the same physical subnet as the ME and the TFTP server (if separate).

setup TFTP server with image
One can be found at (www.solarwinds.com). Confirm that the IP address of the TFTP server matches DHCP option 66. Also, make sure the name of the image corresponds with option 67 of the DHCP server. Make sure the TFTP is running and that the image file is located in it's root directory. It's probably easiest to run the TFTP server on the DHCP server.

boot device and it will download image
Watching from the TFTP server one should be able to see the image file being uploaded the the module.

reboot device and it should be fine then.
After a short period of time after the download, the module should reboot itself. After this the image should be recovered.