@robert-hh Thanks I agree busy-waiting is bad, my understanding was that machine.idle() would give other threads/interrupts the opportunity to run. That code was added to aid the debugging, to see activity while waiting for the network layer to configure itself. I've substituted your code but unfortunately it hasn't changed the networking behaviour - still no IP layer connectivity.

@jcaron Thank you very much for your reply. Turning off WiFi on boot seems to fix the issue. Apparently it was related to the PyCom starting in AP mode for telnet.

@jardar I had the same question today. (Funny coincidence.) I found this by searching the forum: "The only optimisation at the moment is enabling WLAN Power Saving in STA mode (basically the WiFi radio only 'wakes up' at the beacon interval set by your gateway) so you'll see current go down to about 50mA and then 100+ mA at the wake intervals. This is done by re-initilizating WLAN with power_save=True option. However it's not perfect yet, it may caused network timeouts for some people so it became disabled again by default." (Source)