When I use the e-tube software via bluetooth on my android device (phone and tablet) to perform Di2 system updates (check firmware, load preset bike settings, etc.) once the process is complete my Di2 system goes totally dead. Levers/buttons don't do a thing. Likewise pushing the button on the main junction box. Not lights or change of function. Only way to wake up the system is to remove my seat post and disconnect the internal battery for 10 seconds. After that all works fine.

I have the latest version of e-tube and the firmware on all of the devices is up to date. Anybody else have this issue?

Hard wired use of e-tube software on my PC seems to work OK but I'd like to be able to do it "out in the wild" via my bluetooth phone if needed. I don't carry a torque wrench in my pocket and reinstalling my seatpost after accessing the battery requires the max allowable torque to be secure.

What happens if you just unplug the cable coming up the downtube, from where it plugs into the A Junction ?. Power remains to the F & R derailers, but not the A Junction, which has some brains in it.

Also, call/e-mail Shimano, they might have a fix.

I have to unplug it right at the battery. From the A Junction doesn't wake up the system. I do have the EW-WU111 (bluetooth junction box) installed between the battery and the A Junction. Seemed like the easiest and most logical place to install it.

A junction is at the stem, 3 or 5 port. B junction is inside near the b-bracket, it’s the 4 port

I assume you put the WiFi unit between the battery and B junction in the seat tube, good spot for it, but sounds like the WiFi unit might be bad.

What battery do you have?

Basic troubleshooting

1. Attach it to a PC, run E-Tube and check for errors.
2. Re-flash firmware
3. swap out parts with known good. It helps to have friends with Di2.

You will find the problem.

Steve B is probably right about the bad wireless unit.

Another thought is borrow an iPhone/iPad, Download the software and see what happens on that OS. If problem continues it’ll somewhat point to a Shimano device issue.