Re: Raspberry Pi 4 ethernet issues with latest UEFI and 11.0_RC6

On Sun, Jul 26, 2026 at 4:47=E2=80=AFPM John Klos <[email protected]> wrote:
>
> Hi,

hello,

>
> On both a Raspberry Pi 4 and a Pi 400, I've noticed that genet0 ethernet
> doesn't work a good fraction of the time after boot.
>
> This happened infrequently in the past, with older UEFI and older version=
s
> of NetBSD 11. I've recently updated to the latest UEFI version 1.52 and
> NetBSD 11.0_RC6, and the problem seems to still happen on the Pi 4 and no=
w
> it happens very often on the Pi 400.
>
> When this happens, genet0 is configured, and tcpdump shows packets coming
> in, but nothing goes out.
>
> Occasionally, the network interface can communicate with certain hosts,
> but not others, as if MAC filtering works selectively, or something like
> that.

Have you seen some messages like this in dmesg?

> [     1.000004] genet0: Ethernet address f5:77:00:f2:3a:3b
 :
> [     1.000004] autoconfiguration error: The multicast bit is set in the =
MAC address. It's wrong.

If uefi firmware is v1.41 or later, RD4(UMAC_MAC[01]) return 0.
genet_get_eaddr() tries to invent mac address, but it needs htobe().

> Has anyone else experienced this yet? If someone who knows how to diagnos=
e
> would like serial console access to the Pi 4 to see what's up when this i=
s
> happening, please reach out.
>
> Thanks!
> John