I have a Pixma PRO-100 with firmware 1.040, trying to update to 2.031. It fails with the following message:
"Send error occurred during the printer function update."
I do see it go through the process of verifying the existence of the printer, including identifying the current firmware version. I've tried connecting multiple different USB cables and even tried from multiple computer, both were using Windows 10.
Before starting, all printer functions are normal. I've power cycled it and it is not trying to print or perform any other functions prior to starting the firmware update. When updating, the lower LED on the printer is usually flashing, but sometimes also solid.
I'm using the firmware from this page:
What more can be done to troubleshoot this?
There are myriad posts about this on the site.
Bottom line - the 2.X firmware update only applies to printers that came with original 2.X firmware. It is not compatible (or needed) with printers with 1.x firmware.