Avoid The Intel I225-V Ethernet Controller

When I built my own NAS with an Asus ROG Strix B550-F Gaming WiFi II motherboard, I barely noticed its use of the Intel I225-V ethernet controller for the onboard 2.5GBE port. Intel has a good reputation for ethernet controllers and after all, shouldn’t stable ethernet be a solved problem? Find out why you should avoid Intel’s 2.5GBE ethernet controllers like the plague.

The Problem

I noticed that my NAS would randomly go offline around once a month. Network connectivity would be lost and reconnecting the ethernet cable didn’t fix it. Since I run the NAS headlessly, I control it over the network. Hence, I was forced to do a hard reset to restart it every time this happened.

I thought this was a fluke at first. In Oct 2024, I started investigating once the NAS went offline for the third time in as many months. The job of a NAS is to be available to serve data and the apps that I selfhost, so I was very concerned with the instability.

When it goes offline, the following messages are logged:

Oct  2 05:01:48 truenas kernel: igc 0000:06:00.0 enp6s0: NIC Link is Down
Oct  2 05:01:48 truenas kernel: br0: port 1(enp6s0) entered disabled state
Oct  2 05:01:54 truenas kernel: igc 0000:06:00.0 enp6s0: NIC Link is Up 1000 Mbps Full Duplex, Flow Control: RX
Oct  2 05:01:54 truenas kernel: br0: port 1(enp6s0) entered blocking state
Oct  2 05:01:54 truenas kernel: br0: port 1(enp6s0) entered listening state
Oct  2 05:02:00 truenas kernel: igc 0000:06:00.0 enp6s0: NIC Link is Down
Oct  2 05:02:00 truenas kernel: br0: port 1(enp6s0) entered disabled state

The NIC enters a disabled state and never recovers. This is followed by a crash a few minutes later.

Oct  2 05:28:16 truenas kernel: task:IoThread        state:D stack:0     pid:1624  ppid:1      flags:0x00004002
Oct  2 05:28:16 truenas kernel: Call Trace:
Oct  2 05:28:16 truenas kernel:  <TASK>
Oct  2 05:28:16 truenas kernel:  __schedule+0x349/0x950
Oct  2 05:28:16 truenas kernel:  schedule+0x5b/0xa0
Oct  2 05:28:16 truenas kernel:  schedule_preempt_disabled+0x15/0x30
Oct  2 05:28:16 truenas kernel:  __mutex_lock.constprop.0+0x399/0x700
Oct  2 05:28:16 truenas kernel:  igc_resume+0xfe/0x200 [igc]
Oct  2 05:28:16 truenas kernel:  ? __pfx_pci_pm_runtime_resume+0x10/0x10
Oct  2 05:28:16 truenas kernel:  __rpm_callback+0x44/0x170
Oct  2 05:28:16 truenas kernel:  rpm_callback+0x35/0x70
Oct  2 05:28:16 truenas kernel:  ? __pfx_pci_pm_runtime_resume+0x10/0x10
Oct  2 05:28:16 truenas kernel:  rpm_resume+0x56e/0x7b0
Oct  2 05:28:16 truenas kernel:  ? srso_alias_return_thunk+0x5/0xfbef5

This Intel support page describes the issues I experienced and suggests updating the Non-Volatile Memory (NVM) firmware on the controller. However, since it is integrated with the motherboard, I can’t use Intel’s NVM update utility and needed to get it from Asus.

In my research, I found numerous reports of issues with the I225-V controller. There are 3 revisions of the I225-V, and Intel even released an I226-V, which supposedly contains fixes for the issues with the I225-V.

Using the lspci -vv command, I found that the controller on my motherboard is the second revision, so these problems are not surprising.

Intel’s 2.5GBE controllers are not as well tested, since 2.5GBE is much less widely deployed in enterprise environments as it arrived when 10GBE was already mature. Businesses went straight from 1GBE to 10GBE when more bandwidth was needed.

If I had known, I would have gotten a different motherboard or used a separate NIC instead of relying on the onboard controller.

Bricking My Ethernet Port with Official Asus Firmware

Since Asus didn’t offer the NVM update utility on the drivers page for this motherboard, I opened a support ticket describing the issue and asking for an NVM update package that I could run on Linux since the NAS was running TrueNas Scale.

Asus support sent me an NVM update package for Windows. When I repeated my request for a Linux package, this was the response I received:

We are unable to offer the Linux version, as Intel exclusively provides a Windows version and does not support Linux.

I don’t know if this was incompetence or an attempt at gaslighting. I called them out on their excuse, providing a link to Intel’s ethernet driver pack, which contains an NVM update package for Linux.

Asus never got back to me with a Linux version. By then, 2 months had elapsed since I first reported the issue. I gave up on waiting.

In Dec 2025, I installed Windows on a spare SSD to run the Windows NVM update tool they provided. The tool ran partially before bailing out with an error. Unfortunately, it permanently damaged something on the onboard I225-V controller in the process.

The ethernet port on the motherboard would no longer work.

At first, Asus tried denying me support because I bought the motherboard from outside Singapore, since I got it from Amazon. After a strongly worded reply, they stressed that any support they provide is done on an exceptional basis. This made my blood boil.

To add insult to injury, Asus couldn’t provide a software fix to unbrick the ethernet controller. I asked for a partial refund since only the onboard ethernet was broken. Asus wasn’t able to do so and asked me to return the motherboard for diagnosis.

Since I didn’t have a spare motherboard to keep my NAS running, this meant either weeks of downtime or buying another motherboard to use while I sent this motherboard for repair. Since that didn’t make sense, I gave up on getting the bricked ethernet controller fixed.

This will be my last purchase from Asus. I can understand why they couldn’t give me a partial refund, but this happened running firmware directly from Asus support. Trying to deny support because I bought the motherboard from overseas is also inexcusable, since Asus has a strong presence here in Singapore and the motherboard was still under warranty.

Finding A Replacement NIC

I needed something to tide me over when the controller was bricked. I saw a positive review for Plugable’s 2.5G USB to Ethernet Adapter by ServeTheHome, so I bought it since this was something I could get delivered to me quickly.

Unfortunately, it didn’t work well with TrueNas Scale, causing kernel crashes soon after boot.

Since the NAS was already down due to these network issues and I was intending to do so already, I decided to migrate to Proxmox. My streak of bad luck finally ended when the adapter ran perfectly on Proxmox.

In Jan 2025, it was clear that I wouldn’t be able to fix the onboard ethernet controller. I wanted a more permanent solution. I didn’t feel comfortable with using a USB adapter in the long run.

Since my network didn’t support speeds faster than 1GBE, I got an inexpensive 2-port card based on the Intel I350AM2 controller from 10Gtek.

My NAS’s network connectivity has been completely stable with this NIC. Unfortunately, this was not the end of my networking troubles due to a kernel regression causing similar crashes for the I350 controller.

Conclusion

For anything important like a NAS that must be online all the time, avoid the Intel I225-V. If you really need 2.5GBE, use the I226-V instead. Better yet, avoid Intel’s 2.5GBE controllers entirely.

If you plan to use onboard ethernet ports on a motherboard, check for Linux support and ensure you can update the firmware for the onboard ethernet controller.

I would also avoid Asus products.