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Thread: Teensy 4.1 Failed After Automatic Bootloader Update

  1. #1

    Teensy 4.1 Failed After Automatic Bootloader Update

    I recently updated to Teensy Loader 1.56 after using an older version (unsure what the old version is).

    I have two devices, the first one updated the bootloader automatically updated no problem. The second one failed to update the bootloader and now seems to be stuck in some bricked state.

    - Bootloader upload seemed to finish successfully, no error codes were shown
    - When plugging in to windows the PC does not recognize a USB device
    - When plugging in, after about 8 seconds the red bootloader/programming LED starts flashing at 1 second on/ 1 second off

    1. What is this state?
    2. Is it possible to recover the bootloader?

    This is pretty frustrating because the teensy loader didn't give any warnings about the bootloader update, it just did the update and failed and now it seems like my device is bricked...

    Thanks for any help!

  2. #2
    I also performed the "Memory Wipe & LED Blink Restore" from the T4.1 product page.

    - Holding the button caused the LED to go off for 13 seconds, then a short blink occurs, then the LED goes back to blinking at 1Hz on and off. The programmable LED does not change state.

  3. #3
    I restarted my computer and rebooted the device again and it all worked, I think there was something strange in the USB communications but the device is not bricked!

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