HJC Smart 21b intercom problems after firmware 1.3 update

Sean Russell

8. November 2025 16:06

Hi all.

I've successfully updated both mine and my wife's HJC Smart 21b units to firmware v1.3. After doing so, bluetooth audio from Android phone stutters and becomes choppy and the intercom audio fails after around 15 - 20 minutes of use. Both helmets are still connected, we just lose the ability to communicate. If I call her on the phone while we're riding, it connects and we can talk again. Stop the call and it reverts back to a silent intercom connection. Restored firmware back to 1.1 and performed a factory reset and the problem disappeared. Reapplied the v1.3 update and the stuttering and dead audio problem reappears. Also, both intercom units regularly lock up and can only be brought back to life with the reset button. Bluetooth audio from the phone to any other device, headphones, Bluetooth speaker, etc is faultless. Firmware has been restored and updated a couple of times just to make sure the problem is consistently present. Has anyone else encountered this problem and / or found a solution. Could it possibly be down to a firmware configured data buffer being too small or  general software bug? 

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  Haiko

  27. März 2026 11:02

  Hello Sean,

  I have similar issues with the HJC 21B set, only I do not have the driver 1.1

  Are you willing to send me this driver so I can downgrade my unit back to V1.1?

  I tried to get it from Sena/HJC, but appearantly they are not willing to supply it to me.

   

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  Sean Russell

  30. März 2026 18:26

  Hello Haiko,

  To roll back to driver v1.1 I use the Firmware restore button on the Smart HJC Device Manager programme.

  Incidentally, as I've just plugged my helmet into my computer and fired up the device manager programme, I see there's a new v1.3.1 firmware update waiting to be installed. I'm going to update both helmets to the new firmware and see what happens. Wish me luck.

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  Haiko

  1. April 2026 11:35

  Hello Sean,

  I did the update to v1.3.1 and unfortunately I ended up with the same issues, so no improvement regarding communication.

  If I want to downgrade to v1.1 again the computer is asking for the v1.1 driver set. I don't have the v1.1 driver set on my computer.

  Is it possible that could supply me this driver? Because appearantly you have it somewere on your computer if you are able to downgrade to v1.1 again.

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  Sean Russell

  1. April 2026 19:45

  Hello Haiko.

  I've just tried the restore button on the HJC manager, just to see how far I can roll back the firmware and to verify that the file is there. Now all it says is that no firmware package exists to restore. The only image file I have in my downloads folder now is the one for v1.3.1 firmware. I can't even roll back to v1.3. I don't know whether the HJC programme itself has removed the previous firmware images or if my drive cleaner has done it.

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  Haiko

  2. April 2026 19:45

  Hello Sean,

  I hope for your sake that the lastest update works for you :-). Once more I will contact HJC and try to get the original driver set. Hopefully HJC will cooperate. If they send it to me I will let you know.

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  Sean Russell

  3. April 2026 15:45

  Hi Haiko.

  So far the update seems to have improved at least some things. I haven't had chance to try the new update in the wild yet, but I'm hoping to get out on the bike this weekend to give it a go. I did sit in the house for a couple of hours with my helmet connected to my TV (yes, I looked a little strange lol) and the connection was perfect. Absolutely no lag, stutter or choppy audio. I still need to test that the intercom connection between my wife's helmet and mine doesn't still drop off, but to do that I need her to be on her bike and she's a fair weather rider, so no idea when I'll get the chance to do that.

  I'm searching the Internet for the v1.1 firmware for you, but having no luck at all. If I do manage to find it, I'll be sure to let you know.

  All the best, my friend and I hope you get your problem sorted.

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