This article applies to SmartSense Gen. 2 (2025+) only, and covers how to update the firmware on the Garmin eRTL615/616 radar + taillight unit.
Check your firmware version
To verify the firmware version of your radar/taillight, open the Cannondale App and go to Garage. (Add your bike if it’s not there yet.) Tap into your bike’s SmartSense settings screen, then scroll to the bottom—the current Firmware version (radar/taillight) is listed there.
If your Firmware is less than 7.33 it should be updated. Follow the steps below.
How to update eRTL615/616 radar/taillight firmware using a PC/Mac computer
- Remove the SmartSense battery from your bike
- Install the Garmin Express™ application on your computer if you don't already have it
- Follow the instructions at this link to update the radar/taillight
- Reinstall the SmartSense battery into the bike
- A few seconds after the radar gets power it will quickly start applying the firmware update.
The radar LED flashes blue and green to indicate the device is updating and may pause and change patterns during the update. When the update is complete, the LED flashes green 10 times. This may take around 10 minutes. - Verify the firmware update was successful in the app (see above)
How to update eRTL615/616 radar/taillight firmware using an iOS or Android phone
- Install the Garmin Varia app on your phone if you don't already have it
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Follow the instructions at this link to update the radar/taillight
The radar LED flashes blue and green to indicate the device is updating and may pause and change patterns during the update. When the update is complete, the LED flashes green 10 times. This may take around 10 minutes. - Verify the firmware update was successful in the app (see above)