Brown Out Reboots Servers: NVIDIA Drivers Vanish, Ethernet Dies – Sneaker-Net Rescue with a Bare USB Stick
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:author: Russell Ballestrini
:slug: nvidia-breaks-ubuntu-ethernet-linux-modules-extra-fix
:date: 2025-11-06 11:51
:tags: Code, DevOps
:status: published

Two identical Ubuntu 24.04.2 boxes, both running ML workloads on NVIDIA GPUs. A brownout rolls through the neighborhood—lights dim & both machines abruptly power-cycle. Unlike my other systems with UPS protection, these servers lack battery backup & go down hard. They come back up, login prompt intact, but ``nvidia-smi`` returns *nothing*. Drivers gone. No problem—``sudo ubuntu-drivers autoinstall``, reboot, and… oh no. Ethernet vanishes. ``ip link`` shows only ``lo``. No ``eth0``, no ``enp3s0``, no nothing. Both servers, perfectly synchronized in failure.

The culprit? The NVIDIA install (or the kernel update it pulled) silently removed ``linux-modules-extra-6.14.0-35-generic``. Without it, the Intel ``igc`` NIC driver refuses to load. No network, no ``apt``, no recovery—classic isolation trap.

Physical access: check. Internet on another machine: check. Ubuntu installer USB? Nope—this time, I went full sneaker-net with a **blank USB stick & one precious .deb**.

Use ``uname -a`` to get the exact kernel version for the deb file.

On a working laptop:

.. code-block:: bash

  wget http://archive.ubuntu.com/ubuntu/pool/main/l/linux-hwe-6.14/linux-modules-extra-6.14.0-35-generic_6.14.0-35.35~24.04.1_amd64.deb
  cp linux-modules-extra-*.deb /media/user/USB/

Eject. Run down to the rack. Plug USB into **Server #1**.

Boot normally (no live disk—just the regular system). Log in at console.

.. code-block:: bash

  lsblk
  # Spot the USB: probably /dev/sdb1, mounted under /media/ubuntu/USB or similar
  sudo mkdir -p /mnt/usb
  sudo mount /dev/sdb1 /mnt/usb
  ls /mnt/usb
  # → linux-modules-extra-6.14.0-35-generic_6.14.0-35.35~24.04.1_amd64.deb

Install it:

.. code-block:: bash

  sudo dpkg -i /mnt/usb/linux-modules-extra-*.deb
  sudo depmod -a

Reload the NIC driver:

.. code-block:: bash

  lspci -nnk | grep -i ethernet
  # → shows "Kernel driver in use: igc" (or should)
  sudo modprobe -r igc
  sudo modprobe igc
  ip link
  # → enp3s0 appears!

``nvidia-smi`` is back. Server #1: **saved**.

Realtek RTL8125 NIC on the Second Server
=========================================

Ah, the classic "identical" servers with a twist—one Intel, one Realtek. The RTL8125B (common on modern boards) uses the ``r8169`` kernel module in Ubuntu 24.04.2. The fix is nearly identical to the Intel one, just swap the driver name in the reload step.

Reload the Realtek NIC driver:

.. code-block:: bash

  lspci -nnk | grep -i ethernet
  # → shows "Kernel driver in use: r8169" (or should)
  sudo modprobe -r r8169 2>/dev/null || true
  sudo modprobe r8169
  ip link
  # → enp3s0 appears!

Both servers: **fully recovered**. One USB stick, two different NICs, same root cause. The missing ``linux-modules-extra`` package strikes again.

Bonus: Mouse Drivers Too
========================

It's not just NICs. The ``linux-modules-extra`` package also contains drivers for various USB mice & peripherals. If you boot into a system where your mouse suddenly stops working after an NVIDIA driver update, you're likely hitting the same issue. The HID drivers for many Logitech, Razer, & other gaming mice live in ``linux-modules-extra``.

After installing the package & running ``sudo depmod -a``, either reboot or manually reload the HID modules:

.. code-block:: bash

  sudo modprobe -r usbhid
  sudo modprobe usbhid

Your mouse should spring back to life. Same root cause, different symptom—the NVIDIA installer's collateral damage extends beyond networking.
