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Recovering a Bricked Notecard

If the wrong type of firmware was inadvertently uploaded to your Notecard, or a firmware update was interrupted before it finished, you may need to manually recover the "bricked" Notecard using a Notecarrier.

Every recovery procedure below works the same way: it forces Notecard into its bootloader by holding BOOT (pin 65) at VIO while Notecard is reset, then releasing NRST (pin 67) before releasing BOOT. The bootloader resides in the STM32's read-only system memory and cannot be erased, so these steps work regardless of what was previously written to Notecard's flash memory. Most Blues Notecarriers expose the BOOT pin for this exact purpose.

note

These procedures apply to Notecard Cellular, Notecard Cell+WiFi, Notecard WiFi v1, and Notecard for Skylo.

warning

These procedures cannot recover a Notecard that was erased using the "Full chip erase" option in STM32CubeProgrammer. That option removes factory provisioning data in addition to firmware, and reflashing a firmware binary does not restore it.

Recovering a Notecard with Notecarrier A

  1. Download the appropriate firmware binary for your specific Notecard.
  2. Plug the Notecarrier A into your PC — micro USB on v2.0, USB-C on v2.3.
  3. Add a jumper wire between the BOOT pin (pin 10 of the 22-pin header) and VIO (pin 4 of the same header). BOOT is unlabeled on Notecarrier A v2.0 and earlier, so use the image below to locate it.
  4. Add another jumper wire between RST and VIO.
  5. Remove the RST/VIO jumper.
  6. Remove the BOOT/VIO jumper.
  7. Notecard is now in its bootloader, so you can flash a firmware binary using STM32CubeProgrammer, following the branch of those instructions that matches your Notecard. Skip the bootloader command, as the steps above have already placed Notecard in its bootloader.

recovering notecard with notecarrier a

Recovering a Notecard with Notecarrier F

  1. If there is a host MCU in the Feather socket, remove it.
  2. Download the appropriate firmware binary for your specific Notecard.
  3. Plug the Notecarrier F into your PC via a micro USB cable.
  4. Add a jumper wire between N_BOOT and N_VIO.
  5. Press the small reset button next to the Notecard socket labeled N_NRST (see image below).
  6. Remove the N_BOOT/N_VIO jumper.
  7. Notecard is now in its bootloader, so you can flash a firmware binary using STM32CubeProgrammer, following the branch of those instructions that matches your Notecard. Skip the bootloader command, as the steps above have already placed Notecard in its bootloader.

recovering notecard with notecarrier f

Recovering a Notecard with Other Carrier Boards

If using another Blues Notecarrier (or your custom carrier board routes BOOT (pin 65), NRST (pin 67), and the USB signals to accessible test points) you can recover a Notecard as well.

Notecarrier X, XI, XM, and XS expose Notecard's pins on a 16-pin header, with VIO on pin 4, BOOT on pin 5, and NRST on pin 6.

warning

The same 16-pin header carries a second pin silkscreened BOOT, at pin 13, grouped under an ALT DFU label alongside NRST at pin 12. Those two are Notecard's Outboard DFU outputs — signals Notecard drives into your external host MCU — and jumpering them will not put Notecard in its bootloader. Use pin 5, the one next to VIO on pin 4.

Two carriers cannot perform Notecard recovery:

  • Notecarrier CX does not route Notecard's pin 65 at all. The header pin labeled BOOT on Notecarrier CX is selects the bootloader of the Notecarrier CX’s own host MCU.
  • Notecarrier Pi does not route Notecard's NRST (pin 67).

To recover a Notecard on any other carrier that does route these pins:

  1. Download the appropriate firmware binary for your specific Notecard.
  2. Connect your carrier board to your PC so the Notecard enumerates over USB.
  3. Connect BOOT to VIO.
  4. Momentarily connect NRST to GND, then disconnect it.
  5. Disconnect BOOT from VIO.
  6. Notecard is now in its bootloader, so you can flash a firmware binary using STM32CubeProgrammer, following the branch of those instructions that matches your Notecard. Skip the bootloader command, as the steps above have already placed Notecard in its bootloader.