Reflash p1 using only swclk, swdio (and power and ground)?

hi all

we have a couple of devices with a p1 and made a mistake not connecting reset and mode correctly. as long as all is well the are not needed… we have some precautions in the code we flash (long delay) so we could reflash the device is something wrong with the code

but you guessed it… something went wrong and we cannot reflash them. we did bring out the swclk and swdio pins (d6, d7). is it somehow possible to reflash using these and a programmer? or are they bricked forever?

thanks
frank

Yes, you can reflash a P1 using SWD (SWDIO, SWCLK, and GND) using a SWD programmer like the ST-LINK/V2 or the Particle Debugger.

The issue you will run into is that once Device OS boots, the device will no longer respond to SWD (unless you have a SWD-enabled version of Device OS installed). When you have RESET and MODE the easiest solution is to enter DFU mode, which does have SWD enabled.

You might be able to get the device to reset halt by SWD, or possibly put a breakpoint in the bootloader, to get it to stop before booting Device OS, if you can’t enter DFU mode.

thanks, will try!