Kai [Bug Fix] — “Could not enable DFU mode”

While updating your dongle if you are unable to put your Dongle on DFU mode, this article would guide you on how to manually enable DFU Mode and update the dongle.

Vignesh Sankar
Mar 10, 2019 · 5 min read

NOTE: This is a known bug and our team is working on the fix. This is a temporary method to help you update the dongle and let you start using the Kai if you are facing the Dongle DFU update issue. This article will guide you through step by step process on how to manually enable dongle DFU mode using Arduino IDE. If you face any problems while trying the fix yourself or would prefer us to schedule a call with you and do the update for you, you can drop us a message at vicara.co and we’ll get in touch with you

Step 1: Turn Kai Off

Make sure your Kai is turned off throughout this process. The LED being off in Kai indicates that Kai is off.

Step 2: Turn Off Kai Control Center and Kai SDK process

The Kai Control Center and Kai SDK process needs to be turned OFF.
Here’s how to do it. (refer the numbers on the images below)

  1. Right Click and ‘Quit’ Kai Control Center from Apps Tray (bottom of the screen)
  2. Turn off Kai SDK by Right Clicking on the icon (Top bar in Mac and System Icons Tray in Windows) and selecting ‘Exit’



Step 3: Reinsert the Dongle

Remove the dongle from the computer and plug in back in.

Step 4: Download Arduino IDE

Download Arduino IDE software for your OS (Windows/MacOS) from the following link: https://www.arduino.cc/en/Main/Software

Step 5: Keeping the Kai Updater App Ready

  • Launch your Kai Updater App on your Smartphone/Tablet
  • Make sure Bluetooth, Location and Internet are turned ON on your mobile/tablet device.
  • ‘Skip’ Step1: Kai Update (First Screen in the app. Skip option can be found below continue button)
  • Once you reach Step2: Dongle Update Screen, press continue to go to Step 1 of 4: Insert Dongle Into USB Port. Press ‘Continue’ again to go to Step 2 of 4
  • Leave the app at Step 2 of 4. We’ll come back to this again.

Step 6: Enabling Dongle DFU using Arduino IDE

  • Launch your Arduino IDE

For Windows:

  • Go to Device Managers and search the Port ID for Silicon Labs CP210x. In this case, the port name is COM4. Yours might be different.
  • Now goto Arduino IDE. From Top Menu Bar, select Tools>Port and select the Port ID you found in the last step. In our case, the Port ID was COM4.

For MacOS:

  • From Top Menu Bar, select Tools>Port>cu.SLAB_USBtoUART

Let’s Enable Dongle DFU Mode:

  • Click on the Serial Monitor Icon. Its a Magnifying Glass icon found on the top right corner of your Arduino IDE. A window will pop up.
  • Set baud rate to 115200 baud as shown in the image below
  • At this step, make sure your app is ready on Screen 2 of 4 of Dongle Update.
  • WARNING: Make sure to NOT update your dongle using Kai firmware on the app. Update only using the update option in Step 2 of 4 in the Kai Updater App. Else it would make your dongle permanently unusable. Follow the steps carefully on how to update the dongle.
  • You should see this screen in your Kai Updater Mobile/Tablet App:
  • Now in your Arduino IDE, Type capital ‘A’ in the box and click on send.
  • As soon as you press send, the dongle will turn Red indicating it's on DFU Mode. Note: The Dongle will stay in DFU mode only for 20 secs.
  • Now quickly go to your Kai Updater Mobile/Tablet app and click on ‘Continue’
  • Your app should now go to Step 3 of 4 and the progress bar will start filling Blue.
  • The bar will fill up and go to Step 4 of 4. Congrats your Dongle is now updated!

If your dongle red light went off in between the update process and your update wasn’t successful. Please go back to Step 2 of 4 on your app. Now go to Arduino IDE, Type ‘A’, click send again and repeat the last step.

Step 7: Continuing with Kai Calibration

  • Unplug and Reinsert you dongle
  • Turn your Kai on. Kai should connect to the dongle and Kai LED should become green.
  • Launch Kai Control Center on your Computer
  • Continue with the Kai Calibration Process by following the OnScreen Instructions

Some phones may not be compatible with Bluetooth LE standards. Try using a different mobile device if you get an error in the app while trying to update the dongle.

This method works well for Enabling Dongle DFU mode. However, if you are stuck at any step or are facing some unknown issue, feel free to reach out to us on our website vicara.co and we’ll help you out.


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