P1 stuck at solid blue first time boot

I was wondering if any one had run into this situation before.

I have been using P1s for a while now and it is the second time I run into the following (didn’t bother to solve it the first time):

  • P1 soldered to a PCB. no shorts, everything looks good (like the ones before)

  • Boot for first time, there was a sequence of white flashes (normal, like the ones before)

  • Instead of going into listening mode flashing blue, the status LED is indicating a solid blue.

  • Can enter safe mode, but then would get stuck again at blue since there was no prior SSID entered

  • I can enter the dfu mode, but the computer doesn’t recognize the dfu device, hardware connections are good.

Has anyone run into this particular problem and/or knows how to solve it?

Hm that is an interesting symptom. Do you have the serial or JTAG pins on the module exposed? If so, you can update the firmware and check to see if it is a firmware or a hardware issue.

If you have serial exposed, you can open up a serial terminal and issue a particle update command, followed by a particle flash --usb tinker command, which should update both your system and user application firmware.

If you have JTAG exposed, you can update your module to the most recent system and Tinker version by following the commands on this page:

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@bing1106 Any luck with this? I’m encountering the exact same issue.

@kmtm, this occured maybe once or twice and I had to move on. I have mounted more than 3 dozen P1s by now. I had the serial pads exposed and was not able to communicate with the modules directly.

May I suggest you check the power input pads specifically for the radio module, namely VDDIO_3V3_WL pin.

I’d be glad to give you more suggestions if you want to give more detail about your PCB layout, namely:

  • Are you using a 4 layer or 2 layer board?
  • What type of caps are you using for supply decoupling? Placements?
  • How often have you encountering this issue? Is it a consistently happening? Have you had any success with the same PCB?
  • How are you assembling the P1s? Reflow? Temperature? Duration? (Excess heat might damage the modules)
  • Do you use via on the solder pads? Different amounts of solder deposited to the pads might cause the P1 to not level with the PCB, causing potential open connections.

You can also PM me if you want.


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It is notated in our Product Creator Guide, but we highly recommend that anyone using the P1 in an integrated design expose both JTAG and serial lines to assist with debugging and reprogramming.

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