Unable to flash Arduino Nano 33 BLE Rev2 with bossac runner in Zephyr (Flash erase failed)

[ltrush]

Hi all,

I’m running into issues flashing an Arduino Nano 33 BLE Rev2 (nRF52840) using Zephyr and the bossac runner. I consistently hit a “Flash erase failed” error and can’t get past it. Please note that I've used ChatGPT to help me format this post but I have verified all information present. 

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Development Setup

• Host OS: Windows 11

• Tooling:

  • west v1.4.0

  • Zephyr v3.1.0

  • Toolchain from nRF Connect SDK installation

  • Visual Studio Code (Nordic extension installed), but I am invoking west from the command line (PowerShell)

• bossac binary: Arduino-provided build

  C:\Users\...\AppData\Local\Arduino15\packages\arduino\tools\bossac\1.9.1-arduino2\bossac.exe

Hardware

• Board: Arduino Nano 33 BLE Rev2

• Target MCU: nRF52840

• Connection: USB, COM4 (bootloader mode confirmed via Device Manager)

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Command

west flash --bossac=C:\Users\luke.trusheim_nzxt\AppData\Local\Arduino15\packages\arduino\tools\bossac\1.9.1-arduino2\bossac.exe --bossac-port=COM4

Output

-- west flash: rebuilding
[0/5] Performing build step for 'blinky'
ninja: no work to do.
[4/5] cmd.exe /C "cd /D C:\ncs\v3.1.0\zephyr\samples\basic\blinky\b...sysbuild && C:\ncs\toolchains\b8b84efebd\opt\bin\cmake.exe -E true"
-- west flash: using runner bossac
Write 21856 bytes to flash (6 pages)
[ ] 0% (0/6 pages)
Flash erase failed
FATAL ERROR: command exited with status 1: 'C:\Users\...\AppData\Local\Arduino15\packages\arduino\tools\bossac\1.9.1-arduino2\bossac.exe' -p COM4 -R -w -v -b 'C:\ncs\v3.1.0\zephyr\samples\basic\blinky\build\blinky\zephyr\zephyr.bin'

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What I’ve Tried / Verified

• Board is definitely in bootloader mode (double-tap reset, correct COM port confirmed).

• Using Arduino’s 1.9.1-arduino2 bossac, not Zephyr SDK’s version.

• west flash --help lists bossac as a supported runner for this board.

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Help please!

At this point I’m stuck. I haven’t been able to get bossac to successfully erase or flash the board. Any help, insights, or suggestions from others who’ve dealt with this issue would be greatly appreciated.

Thanks,
Luke

[Turbo J]

That 3rd party software is not supported here. 

If you wanted to do serious development, get a nordic DK board and use the included JLink debugger over the SWD connection. That way would be supported here.

Pretty sure you can't use zephyr samples unmodified with a bootloader present.

[ltrush]

I am just following the steps outlined by this official Nordic doc: https://docs.nordicsemi.com/bundle/ncs-latest/page/zephyr/boards/arduino/nano_33_ble/doc/index.html

If possible, I would love to make my project work this way, but if that fails I do have a nrf52480 dongle. My goal is to have two Arduino Nano 33 BLEs simultaneously read data over BLE from a "central device". I just don't know if the dongle is capable of being that device.