Bluz can't be Factory Reset - Bricked?


A little bit of backstory:
I’ve been trying to get some existing Core/Photon code running on the Bluz, and getting the SOS (code 9) when deploying via the cloud.

I thought I’d be clever and try to use the python script and a USB-Serial cable to flash a cloud compiled .bin file to Bluz - and was able to successfully flash the firmware several times, but the code clearly was not running.

I can’t say specifically what caused it, but at this point:

  1. The LED doesn’t illuminate when Bluz is powered.
  2. I can enter bootloader setup mode (solid yellow light), but can no longer interact with the bootloader menu using screen.
  3. I can enter Factory reset mode, but the LED stays blue for hours, and doesn’t reset the firmware.

Any thoughts on how to return the Bluz to its former glory?


What USB to Serial adapter were you using? If bluz can enter bootloader safe mode, it seems strange that you can’t interact with it anymore. Could you try unplugging everything, then turning on bluz while holding BTN and enter bootloader setup mode, then power on the USB to Serial adapter?

Also, could you test the adapter to make sure it is still working properly?

Also, could you send me your code? You can email it to if you would like.


Hey Eric,

Thanks for the reply! It looks like the RX line from my adapter was loose, so that’s why I couldn’t send more firmware, or interact with the bootloader menu. After disconnecting wires to confirm that loopback worked, it started magically working again. :confused:

That said, a successful flash of simple blinking LED test code doesn’t change the aforementioned behavior (no LED on power up, no factory reset, etc).

> #include “application.h”
> void setup() {
> pinMode(D7, OUTPUT);
> }
> void loop() {
> digitalWrite(D7, HIGH);
> delay(1000);
> digitalWrite(D7, LOW);
> delay(1000);
> }

Compiled with: particle compile bluz ./



Ok, let’s reflash the system firmware through the bootloader setup more, I hope that will fix your issue.

Have you compiled locally before? Or do you have the gcc tool chain installed?

If not, I can send you the binary necessary, please DM me your email address or reach out to us at

You will follow the exact same procedure with the python scripts and bootloader, you will just point to this new, different file. That should let you recover.

Let me know if you want to build it locally or if you would like us to send you the binary. Thanks!


Hey Eric,

How about both? I’d like to quickly verify that this approach fixes the issue, but being able to compile locally will be helpful in the future.
I’ll DM my email.

Thanks again!