GL-MT300N v2 vs. v1 - USB interfaces no longer "hot swapable"?

I have a configuration I’ve been using with the GL-MT300N v1 that would seemlessly switch between WAN via a 4g LTE USB modem, a tethered Android phone, and a tethered iPhone. I could just unplug one and plug in another, and the router would switch to the correct interface.

I’ve created the same configuration on the GL-MT300N v2, but now once I have a tethered device plugged in and switch back to the USB modem, the device requires a reboot before it correctly switches back to the correct 4G LTE interface.

It appears from the UI that the tether interface is trying to recognize the USB modem on wwan0, whereas in V1 firmware, tether uses eth1 (iPhone) and usb0 (Android) but ignores wwan0. Is there any way to regain the “hot swap” functionality in V2 without having to reboot to switch from a tethered device to USB modem?

Is your modem have wwan0 interface? It is generally for QMI mode.

Actually this should not be related. MWAN3 script use interface in the UCI, not wwan0 or usb0 etc.

Seems Multi WAN is not working as good as v1 in v2. Maybe the following guys can have a check.
@kyson-lok @hansome

Yes, when I create the modem connection, I select /dev/cdc-wdm0 (qmi) and it works great.

Apologies, I grabbed screenshots for each of the sequence steps below, but the forum is limiting me as a “new user” to just one image upload per post.

So here is the sequence on the GL-MT300N V1:

  1. Initial connection with USB 4G modem:

  2. Swap to tethered iPhone:
    (upload://b0szSepQEfKUKJJtfCODwiTJxgG.PNG)

  3. Swap to tethered Android:
    (upload://9ZTe9k6AbIQBiYXpz494spyZcLy.jpg)

  4. Swap back to USB 4g modem:
    (upload://hDhvVRC4GJDuEslrY8TllpVJxZf.PNG)

In each case, the device regains internet without issues. The UI does not show connection for the Android, but there is internet - I setup a new interface for the android tether, which is why there is no IP in the UI.

Now, the exact same configuration on the GL-MT300N V2…

  1. Initial connection with USB 4G modem:
    (upload://Abzj6PTvGJnqr3VZTqPB8vdG2WR.PNG)

  2. Swap to tethered iPhone:
    (upload://hQrMkGCoc3tQNkDTxc6HKWWX5Tz.jpg)

  3. Swap to tethered Android:
    (upload://88jHNjJu8Eba5jaLgmd6duFsjD0.jpg)

  4. Swap back to USB 4g modem: no connection
    (upload://rViRKHEfTZe74c3xYcYGg1Hcxuc.PNG)

  5. USB 4g modem after power cycle:
    (upload://ba7qQrA4a7RPUMUViXNQlOTJzLe.PNG)

The sequence works fine (despite the blank UI) until #4 - swapping back to the USB 4g modem. No connection until #5 - power down, power up.

Any ideas why this is happening?

maybe it is a bug. will check.

Thanks for looking into it. I can add that I upgraded to the latest firmware (2.27) and now, simply unplugging the modem and plugging it back in (without switch to another internet source) requires a reboot for the modem’s connection to be recognized. I can tell from the LED on the modem that it has signal and established connection, but the router does not recognize.