Before I say a word, my children, I have to warn you: What I’m about to teach you here is basically how to mess up your computer. It’s how to make Windows install the wrong driver for a USB device (possibly PCI devices as well). Don’t complain about a headache when you want to switch to the correct driver (or just another one): Once Windows adopts a driver for a device, it develops certain sentiments for it, and will not give it up so easily.

Also, my children, I have to confess that I still use Windows 2000 these days. It’s about time I went on for at least XP, but I have too much installed software to carry with me (none of which will run, I fear, after an upgrade).

Having these issues out of the way, let’s get to business.

My motivation

I bought a brand new Canon EOS 500D, which came with a brand new EOS Digital Solution disk (v20.0, if we’re at it). It’s black, it’s pretty, it autoboots, but it tells me to go &@^%$ myself with my ancient operating system (Windows 2000, as mentioned). Canon’s “support” is more like a black hole, so I’m on my own. All I want is to download the pics to my computer. When I plug the camera in, I get “Found new hardware” but no driver to get it working with.

I was slightly more successful with Linux (Fedora 9, on my laptop). gphoto2 managed to download the images (using command line, which is cool) using PTP (Picture Transfer Protocol) but I want this working on my desktop.

Now here’s the problem in summary: The camera connects to the computer and says: “I was made by Canon (manufacturer number 0409) and I’m a 500D camera (product ID 31CF), and I support the standard interface 6.1.1, which means “Still Imaging”. An XP computer would say “Aha! A camera! Let’s try PTP, even though I’ve never heard about this device!” but a Windows 2000 won’t talk with strangers (if they are cameras, that is).

Drivers for this camera for Windows 2000 are not to be found. I tried to find a generic PTP driver for Windows, but couldn’t find one. There’s a generic interface (WIA), but no generic driver. Then I thought: Since any camera driver would talk PTP with any PTP camera, why not put just any Canon driver to talk with my camera? After all, the driver just transfers files. I hope.

Update (February 5th, 2010): I got the following laconic mail from Canon’s help desk today:

“Dear Customer,

The EOS 500D camera can only be connected to personal computers with either Windows Vista, Windows XP or Mac OS X operating systems. Unfortunately Windows 2000 is not supported”

Wow! That’s a piece of valuable information after having the camera for over six months!

The black magic

It just so happens, that the 400D has a PTP TWAIN driver for Windows 2000 (the installation file is k6906mux.exe). So I downloaded that one, and installed it as is. Which didn’t help much, of course. But it left me the INF file at the destination directory. That allowed me some wicked manipulations.

The trick is to bind the driver’s software to the specific hardware ID. So I opened the INF file, and found the part saying:

[Models]
%DSLRPTP.DeviceDesc%=DSLRPTP.Camera, USB\VID_04A9&PID_3110

That means, “if some device says it was made by 04A9 (Canon) and that its product ID is 3110 (EOS 400D, I suppose)”, use this driver.

Hey, this is an open invitation for intervention! I simply changed it to:

[Models]
%DSLRPTP.DeviceDesc%=DSLRPTP.Camera, USB\VID_04A9&PID_31CF

(actually, I did it on a copy of the file)

And then I went for all these places saying

[DSCamera.Addreg]
HKLM,"%DS_REG%\TWAIN\EOSPTP",DeviceDesc,,"EOS Kiss_X REBEL_XTi 400D"
HKLM,"%DS_REG%\TWAIN\EOSPTP",ModelName,,"EOS Kiss_X REBEL_XTi 400D"

and changed them to something saying it’s a 500D using 400D driver. Just free text so I know what I’m doing.

By the way, you may wonder where I had the 500D’s product ID from. The answer is Linux again. There’s a utility called lsusb, which supplies all that info. You can get it in Windows too, I suppose. I just don’t know how.

Putting it to work

At this point, I plugged in my camera, and powered it on. Windows told me it found new hardware, great, and then asked me to supply a driver (a couple of wizard windows ahead). It actually wants an INF file, so I gave it the one I cooked.

Since the VID/PID in the file match those given by the camera, Windows installed the drivers and associated them with the camera from now on. Mission accomplished.

Did it work?

The truth is that the result isn’t very impressive. Maybe because Canon’s own EOS utility failed to talk with the camera this way, and Picasa’s interface with the TWAIN driver is a bit uncomfortable. But the bottom line is that I can now download the images to my Windows 2000 computer.

On the other hand, maybe it’s this ugly with proper drivers as well. The most important thing is that it works, after all.