How do I update my SM-PCE1 firmware so that I can use E-Tube Project V4?
If you own the SM-PCE1 diagnostics tool then you'll probably want to use that with E-Tube Project v3.4.5 or v4.0.4.
In some cases, E-Tube Project V4 complains that the SM-PCE1's firmware is old.
It doesn't let you update the SM-PCE1, and you cannot use E-Tube Project V4 with an outdated SM-PCE1.
The workaround is simple: you install previous version of E-Tube Project, version 3.4.5, and use that to update the SM-PCE1. Once that is done you can safely use E-Tube Project 4.0.4.
Note that on some older bikes, E-Tube Project 3.4.5 works better than the newer E-Tube Project versions. Either way, you should now be able to use V4 with your SM-PCE1.
Download E-Tube Project 3.4.5 on the Shimano E-Tube Project site or use my E-Tube Project archive page.