If you had a D-fly / Wireless module installed, you could even update firmware using the mobile app - E-Tube Cyclist.
12-speed Di2 firmware updates
Firmware updates for the 12-speed Di2 systems are different. The charger is just a USB cable, and cannot be used to connect the bike to a windows computer.
Instead, you need either the SM-PCE02 tool, or use the E-Tube Cyclist mobile app. All 12-speed Di2 series (DURA-ACE R9200, Ultegra R8100, and Di2 R7100) support BluetoothLE/ANT out of the box.
Looks easy, right? Well.. when it comes to the wireless ST-R9270, ST-R8170, and ST-R7170 hydraulic disc levers, there is a bit of a gotcha - to install firmware updates, they need to be wired to the rest of the system.
If you don't connect the levers to the rest of the system, you simply cannot update them. Note that this issue only applies to the hydraulic disc levers - the rim brake levers are not wireless and are connected by wire by default.
Initially, Shimano said that this would only be a problem the very first time you update the shift levers, and that future updates should be wireless.
Firmware update using E-Tube Cyclist (Android/iOS)
While the app will tell you that there is an update available for your shift levers, it will not let you download and install that update.
If you do not connect the lever to the rest of the system, the update button will be disabled. Let's do that now, and update the shifters.
How do you connect a wireless lever using wires?
So you have this wireless lever... and you need to connect a wire to it. How do you do that?
Ultegra and DURA-ACE 12-speed hydraulic disc levers have one SD300 type port and one satellite shifter port. You can use the SD300 port to connect an EW-SD300 wire.
The R7170 105 shifters do not have any regular E-Tube Ports that you can plug other components into, but that doesn't mean you can't update them.
There is in fact a port on the side of these levers, used exclusively for updates and diagnostics.
The next question is: what do you plug the other end of the wire into?
You've got two options:
- The battery - BT-DN300 has three ports, and only two should be in use
- Use the front derailleur wire and an EW-JC302 inline junction
Rides of Japan did just this, and of course made a video of the process:
Connect your shift lever to the battery
This method is great if you can easily get to your battery. Most bike manufacturers put the battery in the seat post, and therefore getting to the battery is pretty easy.
Note down your saddle height if you haven't already, then take out the seat post to get to the battery.
Now take a long (1200mm - 1600mm) EW-SD300 wire. Plug one end into the battery and the other into the shift lever you want to update.
You can now use the mobile app to update your shift lever.
Note that if the E-Tube Project app is not registering the newly wired connection, you can fix this by disconnecting the app and then reconnecting to the bike.
Update the shifter, repeat the process for the other lever, and you're done.
Connect your shift lever using the front derailleur wire
If you cannot easily get to your battery, this is a pretty good alternative. We can use the front derailleur wire to connect the Di2 levers to the rest of the system. You need a 1200mm-1600mm EW-SD300 wire and an inline junction (the EW-JC302 or EW-JC304).
All that's left to do now is to take your EW-SD300 wire, and connect one end of it to the junction and the other end to the shifter you want to update. If you have two wires and the 4-port junction you can even update both shifters at the same time.
That's it! You can now update one shift lever using the mobile app (Shimano's E-Tube Cyclist manual). Once you've done that, simply connect the wire to the other lever and update that as well.
If the E-Tube Project app is not registering the newly wired connection, then disconnect the app and reconnect to the bike. That should fix the issue and let you update the shifter.
Now that the shift lever has been connected by wire, the text "wired" appears in the lever image, and the update button is enabled.
If yours doesn't show the "wired" label, double-check you used the SD300 port, and not the sprint shifter (bottom) port. The bottom port will not work.
Update using SM-PCE02 tool
Most home users won't own one, but if you do - by all means, go ahead. Update your levers using the SM-PCE02.
You will need E-Tube Project V5 / Professional, so download that if you haven't already.
You then connect the other end of the EW-SD300 wire to an unused port on the shift lever you want to update, and run E-Tube Project V5/Professional. Just make sure you do not use the bottom port, that is for satellite shifters only.
Alternatively, you could use three EW-SD300 wires and a four-port EW-JC304 junction to connect and update both levers at the same time. It's the more expensive option, and since shift lever updates are not all that common, I'm sticking to the update-one-lever-at-a-time approach.
Did that work? If so, you can store the extra wire and junction away for the next update. In case things didn't go as smoothly as you would've liked, keep in mind that your local bike shop will also gladly update the shift levers for you - it should take them about 10-15 minutes.
If you're looking to buy the accessories needed to do the update and feel like supporting the site, I've added (affiliate) links to Amazon, eBay, and Wiggle below - as well as to the component detail pages.