For general use, the software-only reflashing trick can be used if you have an old device.
If the software-only process screws up, or you have a device with newer firmware (version 2.x or later)
you must perform a hardware mod to enable the reflashing process (and open up the Zipit to homebrew Linux apps).
The "5 wire" mod is recommended, and is what most/all people are using today.
This lets you upload ROM images for testing, and gives you a serial port you can connect to.
The "3 wire" mod is included here as a historical note (and an option if you want to reflash many units)
5 Wire - Developer Configuration
PROCEED AT YOUR OWN RISK
Take apart your Zipit device
You will be soldering 5 small wires to the main PCB.
Two solder points are easy to get to, two are a little tricky, and one is very very difficult to solder to.
Run the wires to an RS-232 level shifter. A MAX233A chip (around $5) is recommended.
You connect this to a free serial port of your PC. Current version of PC upload software runs under Windows (haven't gotten around to porting it to Linux)
Wiring points (original scan thanks to Andrew Hakman of Yahoo BBS):
Closeup:
Other developer tips:
A simple Windows console program is used to selectively upload new firmware.
REVIEW: move to general webpage
To rebuild the kernel, or build ARM Linux Apps to run on the Zipit, you will need a Linux PC (i386) with the ARM Linux cross compliation tools installed.
When writing software, powering the device from AC only (unplug the battery) is recommended. It makes it easier to hard-reset the device.
An NFS server is recommended for easy file uploads. 'nfs version 3 over UDP' is required.
3 Wire - Repair Configuration
This is a slightly easier version.
Very tricky soldering is not required (only mildly difficult soldering for one contact point).
It does not give you feedback for the first part of the reflashing process.
(See above photos for contact points, but ignore the RxD2 and TxD2 signals)
The 3 Wire mod is not supported by my software, but there are others.
I recommend the 5 Wire mod.
