Shimano EP8 Firmware Update

[CarolinaCrawler]

I picked up a second hand bike with a Shimano EP8 motor. The previous owner tried to update the firmware and struggled to get it done. It currently runs well, but the top speed is 15mph (25kph). I wanted to update the firmware with with the US firmware, but cannot figure out how to do.
Another problem I have is the speed is nowhere near correct. I just checked it against another bike we have and it read 3-5mph faster. I will check it with my phone GPS tomorrow. So not only does it stop assisting at 15mph, but it thinks it reaches 15mph at 13mph. Not fun.

I connected via my phone with the e-tube app but it only lets me lower the top speed from 16mph, not raise it.

I took the bike to the LBS and they connected with the DI2PC and they said there was a problem with the firmware that's currently on it. They said something about how it needed to be downgraded to change the top assist speed? I'm not sure. I just want the US firmware and a top assist speed of 20mph.

 

[CarolinaCrawler]

Just checked via gps on my phone and it’s consistently 5mph faster than actual speed. That means assist stops at 10mph! Very frustrating. Does anyone know the best way to get the correct firmware on the bike and correct the speed?

 

[RustyIron]

You might want to try STUnlocker App. I've seen the controls for changing the parameters you mentioned, but haven't tried to change those.

 

[CarolinaCrawler]

Just to give a little update to this, found a bike shop about 60 miles away that could fix it. They had to plug into the bike and get Shimano on the phone. They had to log in and take over their computer to over ride the settings on the bike. We did a full reset along with measuring the rear tire circumference. This fixed all problems.