try to reflash the Particle keys in DFU mode with:
Download the server public key from https://s3.amazonaws.com/spark-website/cloud_public.der
dfu-util -d 2b04:d006 -a 1 -s 2082 -D cloud_public.der
try to reflash the Particle keys in DFU mode with:
Download the server public key from https://s3.amazonaws.com/spark-website/cloud_public.der
dfu-util -d 2b04:d006 -a 1 -s 2082 -D cloud_public.der