Hi @alzhao I am testing the new 2.23-6 firmware and I can see that now it is trying to get dual-stack but WAN interface does not come up using this config:

config interface ‘wan’
option device ‘/dev/cdc-wdm0’
option proto ‘qmi’
option apn ‘ltedata.apn’
option modes ‘all’

I have also try proto ‘wwan’ too but they get this error:

Thu Oct 27 15:22:17 2016 daemon.notice netifd: Interface ‘wan’ is setting up now
Thu Oct 27 15:22:17 2016 daemon.notice netifd: wan (2934): Waiting for network registration
Thu Oct 27 15:22:17 2016 daemon.notice netifd: wan (2934): Starting network ltedata.apn
Thu Oct 27 15:22:17 2016 daemon.notice netifd: wan (2934): Unable to connect IPv4
Thu Oct 27 15:22:17 2016 daemon.notice netifd: wan (2934): Unable to connect IPv6
Thu Oct 27 15:22:18 2016 daemon.notice netifd: wan (2934): Unable to connect
Thu Oct 27 15:22:18 2016 daemon.notice netifd: wan (2957): Stopping network
Thu Oct 27 15:22:18 2016 daemon.notice netifd: wan (2957): Command failed: Permission denied
Thu Oct 27 15:22:18 2016 daemon.notice netifd: Interface ‘wan’ is now down

@RangerZ what settings are you using for your modem config? I just used the config here How To use LTE modem in QMI mode for WAN connection [Old OpenWrt Wiki] to get the IPv4 connection working. You may also need set the mode for your modem using “uqmi -d /dev/cdc-wdm0 --set-network-modes all” or can force it to LTE using “uqmi -d /dev/cdc-wdm0 --set-network-modes lte”

Thanks