I had a very similar issue, and have fixed temporarily by rolling back. Details below:
Hardware: Intel NUC 11 Panther Canyon (NUC11PAHi7, Core i7-1165G7, 16 GB RAM, single 512 GB NVMe SSD, Intel I225 2.5 GbE Ethernet, wired to a Sky Hub router). ROCK with Roon Server 2.74 (build 1716).
What happened:
- 30 Oct 2026 ~23:53 (UK time) I accepted the update prompt in the Roon app on my Mac. This installed RoonOS 3.0 (build 287) on the ROCK.
- From 23:54 to ~04:06 the Mac remote connected to the ROCK on port 9332 and lost it again after ~34 seconds, every minute (FOUND BROKER / LOST BROKER repeating in Roon_log.txt). That looks like the NUC reboot-looping.
- From ~04:06 the NUC disappeared from the network completely: no ping, no ARP entry, no web admin page, nothing on any other LAN address.
- With an HDMI monitor attached, the ROCK console showed RoonOS 3.0 (build 287) production installed, followed by a “no network link” screen. Normal reboots (several) did not change this.
- I performed the rollback from this thread (three power cuts after the Roon logo). The NUC came back immediately on RoonOS 2.1 (build 271) with Ethernet working, Roon Server still 2.74 (build 1716), and remotes reconnected.
- The ROCK is now offering RoonOS 3.0 (build 287) again; I have set updates to “Ask before downloading” and will stay on 2.1 until a fix is released.
So on this NUC 11, RoonOS 3.0 boots but never brings up the I225 Ethernet port, rather than only crashing intermittently.