

I asked ChatGPT about it since I’m not sure how to go about it, and got this. Might be worth a try.
Prompt: In a recent update to the fedora operating system they changed it so mobile broadband modems are now flagged as WWAN devices rather then ethernet devices. This is causing it to treat a usb tethered phone as a WWAN device instead of a ethernet over usb device, and the tether is not working as a result. How could a user fix this on their system?
Answer: You can teach ModemManager to completely ignore your phone’s RNDIS interface so that NetworkManager will handle it as a normal Ethernet link again. Here’s how:
-
Find your phone’s USB IDs
Plug in your phone with USB‑tethering enabled and run:lsusb
You’ll see a line like:
Bus 002 Device 008: ID 18d1:4ee7 Google Inc. Nexus/Pixel (tethering)
Note the idVendor (here
18d1
) and idProduct (here4ee7
). -
Create a udev rule to ignore it
As root, create/etc/udev/rules.d/99-usb-tether-ignore.rules
with these contents:# Tell ModemManager to ignore my phone’s USB‑tether interface ATTRS{idVendor}=="18d1", ATTRS{idProduct}=="4ee7", ENV{ID_MM_DEVICE_IGNORE}="1"
(Replace
18d1
/4ee7
with your phone’s IDs.) citeturn5search4 -
Reload udev and restart services
sudo udevadm control --reload-rules sudo udevadm trigger sudo systemctl restart ModemManager NetworkManager
After that, your tethered phone will no longer be treated as a WWAN modem but as an ordinary USB‑Ethernet device—DHCP will kick in and Internet will flow as before.
Tip:
If you never use a cellular modem on this machine, you can also just uninstall ModemManager entirely:
sudo dnf remove ModemManager ``` citeturn5search4
I run Debian Stable. I wanted something i could just set and forget. I don’t need updates, or want them outside security stuff. And i want stability. My machines pretty old so i dont need newer drivers or anything anyway. It also has all the software i need.