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Bug with Sram Red A2 etap 11s after Edge firmware upgrade

stepolin
2 months ago

Hi to all,

here I am again after a year, with the same problem. Unfortunately I accepted the fw upgrade to 27.13 version, and there serious faults in the Garmin-Sram communication are back:

- Indicated gearing continuosly swap between the correct one and the 34-32 combination (which is the shortest one)

- Annoying beep every 10 seconds (but it can be turned off in the settings)

- Sometimes, after powering up the Edge, the rear stop to work! I have to remove the battery, reinsert it and than the derailleur start to work again.

I understand that this bug will never be fixed by the Garmin/Sram support, so again I'm asking how to downgrade to 20.19 fw version, which was the latest working withe the A2 derailleur.

Thanks,

Stefano

  • 0 1 month ago

    Hello again,

    even after upgrading to firmware version 27.14, the bug persists.

    Anyone Who knows how to downgrade?

    Stefano

  • 0 1 month ago

    If you have to reinsert the battery to get the derailleur working, it suggests a fault with one of the AXS components. They should always work regardless of what's connected via ANT+ so you definitely have a problem there. 

    It might just be a coincidence that this has occurred after an update or it could be that the newer Garmin firmware is working better and therefore picking up garbage from SRAM. 

  • 0 1 month ago in reply to George

    Hello, it's very hard to believe it is not a coincidence, but please cosider the sequence of events:

    First of all, I don't have the AXS system, but the revised version (A2) of the original 11 speed eTap system.

    - Edge 840 fw 20.19, Sram eTap A2 derailleur --> no problem. Correct gearing is showing, no disconnection or other issues

    - One year ago I upgraded the Edge firmware to version 21.16. The problems begin: the gearing showing on the Edge continuosly alternate between the correct one and the minimum one, every 5 seconds approximately. A couple of times, at the start of a ride, the rear derailleur does not work.

    - Found a way to downgrade the firmware to older version 20.19 --> everything is right back

    - A couple of weeks ago, I (wrongly) accepted the Edge firmware update to version 27.13, and I'm back with the same problems: the showed gearing always alternates, and occasionally the derailleur doesn't work at the begin of a ride. Prior to the firmware upgrade, the derailleur never missed a beat.

    - Newer Edge firmware is now preventing the downgrade procedure I did last year, so I'm stuck with this version.

    Last year, someone on the forum pointed out where the problem resides:

    Changes made from version 20.19 to 21.16:

    • Added support for button control and trim adjustments for SRAM AXS shifting systems

    which introduced message types not handled by my etap (non AXS) derailleur.

    So, it seems the Sram derailleur is picking up some messages from the Edge 840, but it can't understand them and probably that results in an error blocking the derailleur.

    I think it's a serious problem, but neither Garmin nor Sram is going to fix it, and also the Edge downgrade is not possible anymore: very bad.