The stock STA client interface (wlan0) holds phy0's channel, pinning wlan0mon so 2.4GHz recon captures nothing (verified: iw set channel -> Resource busy until wlan0 is down). env_check now disables it (uci wireless.dummy_radio0 disabled=1 + wifi reload) at startup and /api/recon/status exposes wlan0_sta so the recon page can warn if it regresses.