Unable to unbrick ModalAI Voxl m500

  • Hello there,

    One of our ModalAI drones is bricked and we are unable adb shell into the device. Following the instruction to unbrick given here, I am unable to find device upon sudo fastboot devices.

    Here are the instructions we followed to unbrick the device:

    • Power off the VOXL
    • Detach VOXL USB cable (to ensure USB is not supplying any power VOXL)
    • Attach the USB Expander and Debug Add-On board
    • Ensure the FASTBOOT labeled switch is set to on
    • Ensure the EMERG BOOT labeled switch is set to off
      NOTE: if your board is missing the EMERG BOOT switch, this is OK as its default un-populated state is OFF
    • Power on the VOXL
    • Reattach VOXL USB cable
    • After VOXL boots up (about 5 seconds), set the FASTBOOT back to off

    Here is a video of the attempt https://youtu.be/BDEEefeVZ20

    Please let us know if we have missed any steps. Thank you.

    Ashwin Sushil

  • Dev Team

    Hi @ashwin-umdlife ,

    Sorry this post is shown as 'deleted' for some reason, testing a response.

  • Dev Team

    Hi @ashwin-umdlife ,

    I un-deleted this post, I'm not sure if you meant to delete but was asked from our contact email to look at this post.

    OK, I think we have some timing issues possibly happening here.

    Let's work through this and see if we need to update our documentation.... there's a couple scenarios to work through so it's a little tricky.

    The idea here is that we want to mimic "holding down the volume-down key while powering on a phone and letting go right after you power on" and then run the command.

    So, let's try this:

    • have m500 powered off
    • have fastboot switch turned ON
    • have USB cable connected to m500, not the host (because VOXL can get a little power from USB, but not enough to boot)
    • have your terminal open and ready with sudo fastboot devices command waiting


    • plug USB power in
    • power on m500
    • turn fastboot switch off and quickly run the command (hit ENTER on the terminal that has the command waiting)

    Repeat this several times if possible. If we ever detect a device in fastboot mode then we can next attempt to update the system image.

  • @modaltb I deleted this post because I figure out the usb should be connected to the voxl board and not the expansion board. Thank you making this clear. I see that there is a video made by your team explaining the unbricking procedure. It will be great if you could add it in the office modalai unbricking documentation.

  • @modaltb
    i also try to unbrick my VOXL
    adb - does not work
    but the fastboot sees the device
    Tell me how to properly flash system image using fastboot

  • Dev Team

  • @Chad-Sweet I think we are all commenting on the wrong post here. The issue of this post was solved by connecting to the appropriate usb cable.

    However, @Roman-Rempel I guess you are having similar problem as in this post https://forum.modalai.com/topic/520/voxl-stuck-in-waiting-after-unbricking/3 ?

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