How to do this?

Hi All, Interested in remote usb cable for my PowerShot S3 IS, but as I understand it I need to install CHDK first. The problem I have that firmware in my camera is not compatible with required revision for CHDK installation. From what I was able to figure out, my camera version # is 1.00, the Canon website does not show any firmware upgrades.. Any direction would be much appreciated. Thanks.       

Hi All, Interested in remote usb cable for my PowerShot S3 IS, but as I understand it I need to install CHDK first. The problem I have that firmware in my camera is not compatible with required revision for CHDK installation. From what I was able to figure out, my camera version # is 1.00, the Canon website does not show any firmware upgrades.. Any direction would be much appreciated. Thanks.     

Welcome.

The correct firmware version will look like GM1.00A. It's extremely unlikely that your camera from 2006 has a never before seen firmware version. 100a is the only version known for S3IS, so you can just use that. You may want to use Stick or CHIMP to install https://chdk.fandom.com/wiki/Prepare_your_SD_card

Thank you Sir! Appreciate fast replay and good advice as well. Used stick to get CHDK installed, now I need to learn about its detail. Want to take the opportunity to thanks everyone who is donating their time and effort to do this.
Attached please see snippet from what an 'exiftool(-K)' shown by reading image taken by my S3. Thank again.

Attached please see snippet from what an 'exiftool(-K)' shown by reading image taken by my S3.

Canon labels several different things as "firmware version" and sets two different exif tags. That one isn't the one used to determine which CHDK version you need. See https://chdk.fandom.com/wiki/FAQ#Q._How_can_I_get_the_original_firmware_version_number_of_my_camera.3F

If you wanted to get the version with exiftool, you'd need the "FirmwareRevision" tag, which would give something like
exiftool.exe -FirmwareRevision IMG_0001.JPG
Firmware Revision               : 1.00 rev 1.00
The rev corresponds to the letter, so rev 1.00 is A.

I got it. Followed the link you posted above and it shows ver.100A. Thanks.
Now I need to make the usb shutter trigger cable. It should be no problem because been known to blow up component or two..

There used to be a fellow selling a nice one at a decent rate. I have that somewhere, maybe I'll find where I got it from. Flickr or something... If only this brain would work...

Well, brain does not work but Google does. I got this way back when and liked it:
https://www.flickr.com/photos/fvdk3d/sets/72157624151791739/
Image has contact info to the fellow. No idea if he's still into it.