No wifi connection on Raspberry Pi Zero 2W

Hi folks. I just got my hands on a pi zero 2W and decided to have a play with nerves on it. I ran mix nerves.new, enabled the nerves_system_rpi_0_2, statically configured a wifi SSID and wrote the SD card with mix firmware.burn. I wanted to validate that my dev env was set up correctly and working.

I configured the network thusly:

config :vintage_net,
  regulatory_domain: "NZ",
  internet_host_list: [{"harton.dev", 443}],
  config: [
    {"usb0", %{type: VintageNetDirect}},
    {"eth0",
     %{
       type: VintageNetEthernet,
       ipv4: %{method: :dhcp}
     }},
    {"wlan0",
     %{
       type: VintageNetWiFi,
       vintage_net_wifi: %{
         networks: [
           %{
             key_mgmt: :wpa_psk,
             ssid: System.fetch_env!("DEFAULT_WIFI_SSID"),
             psk: System.fetch_env!("DEFAULT_WIFI_PSK")
           }
         ]
       },
       ipv4: %{method: :dhcp}
     }}
  ]

As far as I understand it, VintageNet will automatically start and connect without any further configuration, right? Looking at the logs in the UniFi console it doesn’t even appear to be trying to connect.

The actual code (such as it is) is available here.

I’m using MIX_TARGET=rpi0_2 and setting the DEFAULT_WIFI_SSID and DEFAULT_WIFI_PSK with an environment variable at build time.

Pointers appreciated.