# Cannot change shift modes on Di2



## koolzero (May 17, 2018)

I recently bricked my Di2 during a firmware update from iPhone. I took the battery to my LBS and they flashed it which resolved the bricked state and it allowed me to complete a firmware update (this time through a PC). 

One thing though that isn’t working is the ability to change shift modes by double pressing on the button on the junction box. I can still connect to it from my iPhone by long pressing it. 

Anyone have any idea on why that may be and anyway to fix it? Is it possibly a bug with the recent firmware?


----------



## Marc (Jan 23, 2005)

Many people have had issues doing firmware updates via bluetooth, in particular updating the BT module wirelessly. I myself had it happen this winter.

The easiest fix...unplug your junction box from the battery...wait a bit and plug it back in. Should get back to working.


----------



## Steve B. (Jun 26, 2004)

Marc said:


> Many people have had issues doing firmware updates via bluetooth, in particular updating the BT module wirelessly. I myself had it happen this winter.
> 
> The easiest fix...unplug your junction box from the battery...wait a bit and plug it back in. Should get back to working.


You need to re-read the OP. He states he got the system un-bricked with help from the LBS and that’s not his current problem (good advice though, about not using an app over BT to update the WiFi unit).

His issue is he cannot get the system to change modes - manual, Synchro, etc... via the button on the A junction box. 

Only suggestion I have is I can use my Garmin 1000 to change shift modes and if you have that option, try it. But not a long term answer as to why the A junction method doesn’t work.


----------



## Marc (Jan 23, 2005)

Steve B. said:


> You need to re-read the OP. He states he got the system un-bricked with help from the LBS and that’s not his current problem (good advice though, about not using an app over BT to update the WiFi unit).
> 
> His issue is he cannot get the system to change modes - manual, Synchro, etc... via the button on the A junction box.
> 
> Only suggestion I have is I can use my Garmin 1000 to change shift modes and if you have that option, try it. But not a long term answer as to why the A junction method doesn’t work.



No, I read his post. The junction no longer having mode-changing is an artifact of the failed flash. De-powering the junction box is a fix for this exact symptom IME.

If you unpolug the Junction and plug it into a PCE1--it'll say "no errors found", because unpowering it descrambles its brain....since the PCE1 can only talk to one Di2 part at a time physically unplugged from everything else.


----------



## koolzero (May 17, 2018)

Ok, so I should try unplugging all 3 cables going to the junction box? How long should I wait?


----------



## Marc (Jan 23, 2005)

koolzero said:


> Ok, so I should try unplugging all 3 cables going to the junction box? How long should I wait?


A few minutes should do the trick. The only power supply for all Di2 gear is the battery.


----------



## xxl (Mar 19, 2002)

Steve B. said:


> You need to re-read the OP. He states he got the system un-bricked with help from the LBS and that’s not his current problem (good advice though, about not using an app over BT to update the WiFi unit).
> 
> His issue is he cannot get the system to change modes - manual, Synchro, etc... via the button on the A junction box.
> 
> Only suggestion I have is I can use my Garmin 1000 to change shift modes and if you have that option, try it. But not a long term answer as to why the A junction method doesn’t work.


Q: Would it be theoretically possible for someone to hack someone else's electronic shifting?

I'm envisioning legions of electro-domestiques, riding up to the opposing team's leader, and pressing a button on a mysterious black box, causing an ill-timed shift....


----------



## tlg (May 11, 2011)

xxl said:


> Q: Would it be theoretically possible for someone to hack someone else's electronic shifting?
> 
> I'm envisioning legions of electro-domestiques, riding up to the opposing team's leader, and pressing a button on a mysterious black box, causing an ill-timed shift....


On Di2, no since it's a wired system. You'd have to get physical access to the bike to plug it in. 
If you had the Di2 wifi adapter, "possibly". You'd still have to manually activate the connection from the Junction Box button, which would be hard to do while riding. If somehow you could put it into pairing mode, then you'd have to access it from the cell phone app, which is (should be) password protected. So you'd need to be in close proximity long enough to hack the password. Once in the E-Tube software, all you can really do is change settings. Possibly brick the system. 


I think with SRAM E-tap it would be more theoretically possible since the shift signals are sent wirelessly. The signals are encrypted. But I imagine there's always a possibility to break the encryption. 
I always thought a more feasible scenario would be to create signal interference. If you had such a device, you could have legions of assistants with them at the top of a climb or at a sprint finish.


----------



## Steve B. (Jun 26, 2004)

Marc said:


> No, I read his post. The junction no longer having mode-changing is an artifact of the failed flash. De-powering the junction box is a fix for this exact symptom IME.
> 
> If you unpolug the Junction and plug it into a PCE1--it'll say "no errors found", because unpowering it descrambles its brain....since the PCE1 can only talk to one Di2 part at a time physically unplugged from everything else.


Ah !, much better. Thanks for this tidbit, good to know.


----------



## Marc (Jan 23, 2005)

xxl said:


> Q: Would it be theoretically possible for someone to hack someone else's electronic shifting?
> 
> I'm envisioning legions of electro-domestiques, riding up to the opposing team's leader, and pressing a button on a mysterious black box, causing an ill-timed shift....


Theoretically on eTap-sure...but it would be a huge PITA, for fringe equipment that even among cyclists is a rarity. The other thing is that the equipment already has to overcome loads of interference to start with. Our air is utterly polluted with EM noise from a million wireless devices all competing for frequency spectrum. Ask anyone who's ever had to manage more than 1 wireless microphone at a large concert hall...it is hell on Earth because of how much EM noise/signal there already is in the air.

Think back to the days of Mavic Zap, the first electromechanical wireless shifting system. A system so advanced it was downright primitive and lacked handshake security...riding by high-voltage power lines could cause some* really neat things to happen.*


----------



## koolzero (May 17, 2018)

Thanks for the tip, unplugging the battery seems to have fixed it.

Ok, now that you helped me fix that I have another question. Even though I can change modes it does not ever seem to shift automatically. I have never been able to get this to work even prior to bricking the Di2. 

Here is a pic showing all the hardware components on my bike: 

https://www.icloud.com/iclouddrive/0O5yZn77NRYfX9XFk3UxVQ7Cg#IMG_3862


----------



## Marc (Jan 23, 2005)

koolzero said:


> Thanks for the tip, unplugging the battery seems to have fixed it.
> 
> Ok, now that you helped me fix that I have another question. Even though I can change modes it does not ever seem to shift automatically. I have never been able to get this to work even prior to bricking the Di2.
> 
> ...


Have you set up synchronized and semi-synchronized shift modes in e-tube either in-app or on desktop? If you don't have an S1 and S2 mode setup, then cycling through the shift modes won't do anything.


----------



## koolzero (May 17, 2018)

That must be what I need to do. Could you walk me through that process. Here is an animated gif I made of my eTube software of how my bike is currently configured. 

https://www.icloud.com/iclouddrive/0UcoiTHSyePk4vJJxI9655N5Q#eTube_Settings


----------



## Marc (Jan 23, 2005)

koolzero said:


> That must be what I need to do. Could you walk me through that process. Here is an animated gif I made of my eTube software of how my bike is currently configured.
> 
> https://www.icloud.com/iclouddrive/0UcoiTHSyePk4vJJxI9655N5Q#eTube_Settings


You the settings shown should be configured for it...are you quickly double-tapping the button on the junction box to change modes? You should see the LEDs on the side flash the code for which shift mode you are in and what the battery status is.


----------



## ljvb (Dec 10, 2014)

tlg said:


> On Di2, no since it's a wired system. You'd have to get physical access to the bike to plug it in.
> If you had the Di2 wifi adapter, "possibly". You'd still have to manually activate the connection from the Junction Box button, which would be hard to do while riding. If somehow you could put it into pairing mode, then you'd have to access it from the cell phone app, which is (should be) password protected. So you'd need to be in close proximity long enough to hack the password. Once in the E-Tube software, all you can really do is change settings. Possibly brick the system.
> 
> 
> ...


Maybe.. maybe not.. It all depends on the security controls built into the DI2 eco system. While pressing the button is normal operation, with the wireless unit, and a vulnerability, a condition where you can access the system without the button press may exist. 

Now I am going to have to bring my bike (I have DI2) to Defcon.. onto the hardware hacking floor I go 

Causing an ill timed gear change might be amusing (or painful if the rider is standing and cranking away up a hill, and you suddenly force a shift to a much higher gear resulting in throwing the rider off balance and whacking his nuts into the stem.... ), a bigger issue might be removing or bypassing the safety code in the battery, and then forcing a thermal runaway condition.. this could cause the battery to explode, and they are not small batteries. That could do significant harm, especially when in the seat post or other enclosed space causing potential shrapnel. 

Again, these are hypotheticals.. but who knows...


----------



## koolzero (May 17, 2018)

My Garmin detects that the modes change when I double press the junction box button and the lights blink corresponding to the mode I’m in. For whatever reason I’ve never been able to get it to work though.


----------

