Hi,
I have DIY AQ Kit 1 and soldered it up last night. I successfully deployed the blink program and the LED flashes. I then moved on to flashing the C02_PM_SHT_OLED_WIFI program. A first I thought it had failed as the final message was:
Writing at 0x00040000... (100 %)
Wrote 394160 bytes (274031 compressed) at 0x00000000 in 6.8 seconds (effective 463.6 kbit/s)...
Hash of data verified.
Leaving...
Hard resetting via RTS pin...
with no further output on the console and no change on the OLED screen (remains black).
However I then set connectWIFI = true; and recompiled and flashed to the device. I could see the AIRGRADIENT wifi network so at least the WEMO D1 is working. I was able to successully join my WiFI network and then I attached the serial monitor. In this output I can see that all my sensors are rerturning what looks like bad data.
First 5 minutes output was like so:
{"wifi":-67,"pm02":0,"rco2":-1,"atmp":0.00,"rhum":0}
http://hw.airgradient.com/sensors/airgradient:<redacted>/measures
400
and then the outout changed (possibly after I registered the device?):
{"wifi":-69,"pm02":0,"rco2":-1,"atmp":0.00,"rhum":0}
http://hw.airgradient.com/sensors/airgradient:<redacted>/measures
200
{"timestamp":1641414720000,"date":"20:32:00","pm02":0,"pm02_clr":"green","pm02_lbl":"Good","pm02_idx":1,"pi02":0,"pi02_min":0,"pi02_max":0,"pi02_clr":"green","pi02_lbl":"Good","pi02_idx":1,"atmp":0,"rhum":0,"wifi":-66}
I have seen some other threads that discuss the particulate sensor can take hours/days to start returning values but I also have null values from the temp and humidity sensors.
My soldering isn’t brilliant but hopefully not that bad 
Any pointers to how I can debug are greatly appreciated.
Thanks
Darren