Also found this online which may help:
You can reset the Wireless passkey for 11-speed Di2 - even if you don't know the current one - by connecting your bike to a windows computer/laptop using the charger. If you're on 12-speed Di2, you need a bike shop to change it for you.
Download e-tube for windows at
https://e-tubeproject.shimano.com
Important: if you're using the charger, SM-BCR2, then the latest E-Tube Project version (V5 / Professional) will not work. You need version 3.4.5 or v4.0.4 from the archive page:
https://bike.shimano.com/en-EU/e-tub...t/archive.html
Personally I prefer version 4.0.4, especially since v3.4.5 no longer connects to the internet for firmware updates. However, in some occassions version 4.0.4 will complain that the SM-BCR2 firmware is 'old'. The fix for that is to download 3.4.5, and use that to connect to the bike once. Doing so will update the BCR2 firmware in the background.
Version 3.4.5 will complain that it cannot connect to the internet, but you can ignore that message and just click 'ok' and 'connection check'.
In v3.4.5 you change the passkey like this:
Connect the bike to your computer using the charger and Junction A
Open the e-Tube windows app
Make a connection by clicking "connection check"
Click "Bluetooth LE settings"
Set a new passkey
If you're using v4.0.4, open the customize screen and then the EW-WU111 details page.
You can now use the passkey you just set to connect to your bike using BluetoothLE/ANT+. The Passkey is required for wireless connections only.
Also: if you really want to update firmware then I recommend using a computer (over USB) rather than the mobile app. It a bit safer. You can update using the mobile app, of course.. but as far as I'm concerned the mobile app's main feature is changing settings easily (out on the road).
More info:
resetting your passkey:
https://bettershifting.com/change-di...ube-app-or-pc/ (2nd half of page)
connecting to computer
https://bettershifting.com/how-to-co...dows-computer/
(disclaimer: my website
. If you're having more problems and can't figure things out don't hesitate to ask)