Updating the firmware

Here are instructions from Canon for updating your firmware and
the original Canon firmware Version 1.1.1 download in case you want to revert back to the original firmware.
Here is the original wasia 300D firmware site.
And the original wasia 300D firmware download page.

Installation

To install the firmware, follow these steps:
1. Unpack "E3kr111B71.rar" or "E3kr111B71.zip".
2. Copy the file with .fir extension to a CF-card. (Avoid using a Microdrive, if you have a CF card *)
3. Make sure you battery is fully charged before performing the next steps!
4. Insert the CF-card into your camera, turn the camera on.
5. Follow the on-screen instructions.

* The microdrive is a fragile mechanical disk drive. It consumes much more power than a CF card. It is just to minimize possible problems, like having bad sectors, etc. However, it has been used succesfully for the firmware upgrade. A CF card would be the most preferred choice, if you have one.

Changing back to original firmware

Why should I revert to the original Canon firmware?
When you have to sent your camera back to Canon for service, it is a good practice to revert to the latest Canon firmware, if possible, to avoid problems with the warranty.
Don't forget to restore the default settings first!
This cannot be done using "Reset" from the menu as it does not affect the Custom-Functions.
You have to do this manually:

- Set FEC to the default value, that is no compensation, in the center position.
- Now you have to go through the Custom menus in order to reset all the CF's to the original 300D settings. Here is a list of default binary values from left to right (The bottom numbers in the CF menu): 0,0,0,0,0,1,0,11,0,0,0,0,0,0,0,0,0
- After the default values have been restored, flash the original Canon firmware (1.1.1) back.

WARNING

WARNING:
This firmware doesn't come from Canon, nor is it supported by Canon. Installation of this firmware may void your warranty. Problems and/or damage of your camera resulting from the installation of this firmware is for your own risk!

Some friends of me and myself are using it without problems so far. But every time you do an upgrade, you'll take a little risk to render your camera "brain-dead", which means it will remain dead after switching on. In other words, it doens't reboot, or hangs during startup. You can't redo flashing, if you're unlucky, and have to sent your 300D for repair.

When you have to sent it for repair, you don't need to explain that you were performing a firmware upgrade on your 300D. Canon service don't need to know this. They only need to know the current behavior: the camera won't boot up. With this information alone Canon can still fix your camera with warranty. I don't expect them to read and compare byte for byte the flashed firmware, if at all possible with your brain-dead 300D.