FIRMWARE FOR EF 35-350mm f/3.5-5.6L USM LENS

[ezduzit94]

Does anybody know of a source for the latest firmware update for a 35-350mm f/3.5-5.6L USM lens?

[johnrmoyer]

My guess is that it was not possible to update the firmware on that lens.
In the Canon Camera Museum: https://global.canon/en/c-museum/product/ef315.html 

[deebatman316]

The ability to upgrade firmware on EF or EF-S was first released in 2012. Cameras released in or after 2012 have the ability to upgrade firmware. Your lens was released in the early 90s predating this.

[ebiggs1]

One of the prices you pay for buying an old lens (very old). Getting it serviced will be another.