docs: Clarify what a logically distinct commit is

"Keep logically distinct changes in separate commits" was being read as
split anything separable, which turns one piece of work into several
commits that only make sense read together.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

.claude/skills/flash-openwrt/SKILL.md

@@ -0,0 +1,37 @@
+---
+name: flash-openwrt
+description: >-
+  Flash a flake-built OpenWrt image onto one of the OpenWrt boxes (currently fergal): build the
+  image, pre-flight the box, back up its config, validate and stage the image, run sysupgrade, and
+  verify what came back. Use when the user wants to flash, reflash, upgrade or sysupgrade an OpenWrt
+  box, or after changing its baked-in package list.
+---
+
+# Flash an OpenWrt box
+
+The canonical, agent-agnostic procedure lives in the repo at
+[`docs/openwrt-flash.md`](../../../docs/openwrt-flash.md). Read it and follow the phases in order.
+
+Key reminders (see the doc for the full steps):
+
+- **Stop at the ⏸ before Phase 5.** Flashing reboots the box and cannot be interrupted partway.
+  Confirm with the user, and confirm a serial console is reachable, *before* writing anything.
+- **Packages are baked into the image**, so a package change means a reflash. Edit the box's list in
+  [`openwrt/default.nix`](../../../openwrt/default.nix), rebuild, and check the built `.manifest` —
+  a package name that doesn't exist is not a build error, it just isn't in the image.
+- **`scp` does not work** on these boxes (no `sftp-server`). Move files with
+  `ssh <box> 'cat > /dev/…' < file` and `ssh <box> 'cat …' > file`.
+- **Detach the upgrade with `setsid`**, not `nohup` (absent on busybox). `sysupgrade` kills the SSH
+  session mid-run, and an attached run dies with it — possibly after the firmware is erased.
+- **Never reach for `sysupgrade -c`.** It needs `/overlay/upper/etc` and aborts *after* erasing the
+  firmware when that is missing, which is exactly the initramfs case. Plain `sysupgrade` already
+  keeps everything in `/lib/upgrade/keep.d/`.
+- **Poll SSH to detect the reboot, never ping.** Successful pings return in milliseconds, so a
+  "wait for down" loop completes instantly and reports nonsense. Sleep between probes; expect about
+  three minutes.
+- **Verify after**, don't assume: revision, management address, package count against the manifest,
+  and that the new packages are present and running.
+
+The images are declared in [`openwrt/default.nix`](../../../openwrt/default.nix); background on the
+outputs and the pinned package feeds is in
+[`docs/deployment.md`](../../../docs/deployment.md#openwrt-images).

AGENTS.md

@@ -212,7 +212,14 @@ in churn.
 - Commit subjects follow `area/scope: Capitalized summary` (e.g. `nixos/home: ...`); keep logically
   distinct changes in separate commits. Aim for 50-character subjects and do not exceed 72
   characters. Wrap commit bodies at 72 columns. A concise body describing the change and its
-  rationale is welcome when the subject alone does not provide enough context.
+  rationale is welcome when the subject alone does not provide enough context — keep it to the
+  essentials rather than restating the diff. `Co-Authored-By` is the only trailer used here; do
+  **not** add a `Claude-Session` link (or any other session/tooling trailer).
+- **"Logically distinct" means unrelated** — two different applications, two boxes that have nothing
+  to do with each other, a drive-by fix that happens to sit in a file you were editing anyway. One
+  piece of work stays in one commit even when it touches a config, several docs and a switch: if the
+  parts only make sense together, splitting them just makes each half unreviewable. Err towards one
+  commit and split when a reader would ask why two things arrived together.
 
 ## Documentation
 

docs/README.md

@@ -29,6 +29,8 @@ Not every box fits this pattern, but **colony** and **home** are organised this
   nixpkgs channels and home-manager (fork rebase, stable bumps, input review).
 - [`install-box.md`](install-box.md) — guided procedure for installing a new box, from the booted
   installer through partitioning, the box config, `do-install` and documentation.
+- [`openwrt-flash.md`](openwrt-flash.md) — guided procedure for flashing a flake-built image onto an
+  OpenWrt box, from the build through pre-flight, `sysupgrade` and verification.
 - [`reference/dns.md`](reference/dns.md) — generated forward and reverse DNS record reference.
 - [`reference/nixos-options.md`](reference/nixos-options.md) — generated per-option reference for
   the custom `my.*` NixOS modules.
@@ -57,6 +59,7 @@ colony (physical VM host, ams1)
 └── darts ──── third-party/customer VM (opaque, not NixOS)
 
 portcullis (bare-metal edge box for Nikhef — staged, not yet in service)
+    └── fergal   OpenWrt SFP+ switch, staged and moving with it
 ```
 
 ## Site: home

docs/deployment.md

@@ -171,6 +171,43 @@ default `/tmp/xchg/dev.key`), so dev VMs can decrypt the boxes' secrets without
 keys. Dev VMs also get DHCP on `eth0`, an SSH port forward (host 2222 → guest 22), and are
 automatically excluded from deploy targets.
 
+## OpenWrt images
+
+The OpenWrt boxes are not NixOS and are not deployed by this flake, but their firmware is built
+here. [`openwrt/default.nix`](../openwrt/default.nix) declares one image per box and packages it
+through [`astro/nix-openwrt-imagebuilder`](https://github.com/astro/nix-openwrt-imagebuilder),
+which drives OpenWrt's official ImageBuilder — prebuilt target packages assembled into a sysupgrade
+image, with no cross-toolchain involved.
+
+| Output | Box | Release |
+|---|---|---|
+| `openwrt-fergal` | [fergal](sites/colony/fergal.md) | `snapshot` |
+| `openwrt-fergal-release` | The same, on the release branch | pinned in `openwrt/default.nix` |
+
+Both are in `ci`, so images are built and pushed to the Harmonia cache like everything else. Build
+one with `nix build .#openwrt-fergal`; the result holds the `-squashfs-sysupgrade.bin` to flash,
+plus a package manifest and an SBOM. Getting it onto the box is a guided procedure of its own —
+see [`openwrt-flash.md`](openwrt-flash.md).
+
+Packages are baked into the image rather than installed on the box. OpenWrt's package server keeps
+only the current build of each feed, so a box that installs packages at runtime stops being able to
+do so as soon as the feed moves on from the firmware it is running. Adding a package means editing
+the image's `packages` list and reflashing.
+
+### The feed pin
+
+OpenWrt's download server is never at rest: snapshot is rebuilt daily, and
+`releases/<version>/packages/` is a symlink to the rolling `packages-<major>` feed shared by every
+point release. Building straight against it fails on hash mismatches and, worse, resolves the
+package list by import-from-derivation — which would drag *evaluation* of this flake onto the
+network and let an OpenWrt feed rebuild break `check-system` for unrelated boxes.
+
+The `openwrt-feeds` input exists to stop that. It holds expanded per-package hashes, so every `.apk`
+is a plain pinned `fetchurl` and no import-from-derivation is involved. Its generated files run to
+hundreds of thousands of lines and are rewritten wholesale on each refresh, which is why they live
+in their own repository rather than here. Refresh the pin with `nix flake update openwrt-feeds`;
+adding a release or target means adding it to that repo's `pins` and regenerating there first.
+
 ## CI
 
 GitHub/Gitea Actions workflows live in [`.gitea/workflows/`](../.gitea/workflows).

docs/networking.md

@@ -267,8 +267,9 @@ public blocks and the per-customer `mail` / `darts` / `jam` prefixes carry custo
 services with their own public addresses (announced by BGP, routed via the host).
 
 This layout is expected to change: [`portcullis`](sites/colony/portcullis.md) is bare-metal edge
-hardware headed for Nikhef that will take over most of `estuary`'s routing. It has no assignments
-yet and the replacement topology is still being designed.
+hardware headed for Nikhef that will take over most of `estuary`'s routing. It has no colony
+assignments yet (only a home `hi` one, from being staged at home) and the replacement topology is
+still being designed.
 
 ## home
 

docs/openwrt-flash.md

@@ -0,0 +1,103 @@
+# Flashing an OpenWrt box
+
+Guided procedure for putting a flake-built OpenWrt image onto a box. The images themselves are
+declared in [`openwrt/default.nix`](../openwrt/default.nix) and described in
+[`deployment.md`](deployment.md#openwrt-images); the boxes are listed on their site pages (today
+that is [fergal](sites/colony/fergal.md)).
+
+Packages are baked into the image, so this runs whenever the package list changes — not only for
+version upgrades. Work through the phases in order; ⏸ marks the point to stop and confirm.
+
+## Phase 1 — Build
+
+```sh
+nix build .#openwrt-<box>
+```
+
+The result holds the `-squashfs-sysupgrade.bin` to flash, plus a `.manifest` listing every package
+in the image and an SBOM. Check the manifest for the packages the change was meant to add — an
+unknown package name is not an error at build time, it just silently isn't there.
+
+## Phase 2 — Pre-flight
+
+Confirm on the box:
+
+```sh
+grep -E 'RELEASE|REVISION' /etc/openwrt_release   # what is running now
+mount | grep -E ' / | /overlay | /rom '           # flash or RAM? (see below)
+uci get network.lan.ipaddr                        # will it come back reachable?
+cat /lib/upgrade/keep.d/*                         # what survives the flash
+df -h /tmp                                        # room for the image
+```
+
+**Flash or RAM matters.** A box booted normally shows a squashfs `/rom` plus a jffs2 `/overlay`;
+one booted from an initramfs has `/` on tmpfs. The initramfs case has its own hazards — see
+[Flashing from an initramfs](sites/colony/fergal.md#flashing-notes).
+
+**Check the address is in UCI**, not just present on the interface. An address added by hand with
+`ip` disappears on reboot and the box comes back unreachable.
+
+`keep.d` normally lists `/etc/config/`, `/etc/dropbear/authorized_keys` and the dropbear host keys,
+so an ordinary flash preserves both access and identity. Verify rather than assume — losing
+`authorized_keys` on a box reachable only over SSH means a serial console recovery.
+
+## Phase 3 — Back up
+
+```sh
+sysupgrade -b /tmp/<box>-config-backup.tar.gz
+```
+
+Fetch it with `ssh <box> 'cat /tmp/…' > local.tar.gz`. **`scp` does not work** — these boxes have no
+`/usr/libexec/sftp-server`, so it fails with `Connection closed`. (`scp -O` forces the legacy
+protocol if you prefer it.)
+
+For a box being flashed off its **vendor** firmware for the first time, back up the whole flash
+first — the vendor partitions hold per-unit MAC addresses and licence data that cannot be
+regenerated. See [fergal's flash layout](sites/colony/fergal.md#flash-layout).
+
+## Phase 4 — Stage and validate
+
+```sh
+ssh <box> 'cat > /tmp/sysupgrade.bin' < <image>.bin
+ssh <box> 'sha256sum /tmp/sysupgrade.bin; sysupgrade -T /tmp/sysupgrade.bin'
+```
+
+Compare the sha256 against the local file, and require `sysupgrade -T` to exit 0. `-T` validates the
+image and its device-compatibility metadata without writing anything, which is the last cheap chance
+to catch a wrong-profile image.
+
+## Phase 5 — Flash ⏸
+
+Confirm before this point. It reboots the box and is not interruptible.
+
+```sh
+ssh <box> 'setsid sh -c "sleep 2; sysupgrade -v /tmp/sysupgrade.bin" \
+  </dev/null >/tmp/upgrade.log 2>&1 & echo detached'
+```
+
+**Detaching matters.** `sysupgrade` kills the SSH session partway through; without `setsid` the
+upgrade dies with it, potentially after the flash has been erased. `nohup` is not available on these
+boxes' busybox — use `setsid`.
+
+Plain `sysupgrade` keeps the config in `keep.d`. Do not reach for `-c` out of caution: it needs
+`/overlay/upper/etc` and aborts *after* erasing the firmware if that is missing.
+
+## Phase 6 — Wait and verify
+
+Poll SSH, not ping. A successful ping returns in milliseconds, so a naive "wait for it to go down"
+loop finishes before the box has even started rebooting. Sleep between probes and wait on something
+that only succeeds once userspace is up:
+
+```sh
+for i in $(seq 1 40); do
+  sleep 15
+  ssh -o ConnectTimeout=5 -o BatchMode=yes <box> 'grep REVISION /etc/openwrt_release' && break
+done
+```
+
+Expect roughly three minutes. Then confirm the revision changed, the management address returned,
+the package count matches the manifest, and the new packages are actually present and running.
+Connecting without host-key overrides also confirms the host keys survived.
+
+If the box does not return, it needs the serial console — have that confirmed as reachable *before*
+Phase 5, not after.

docs/sites/colony/README.md

@@ -33,4 +33,7 @@ The applications running on `shill` are listed on its own page — see
 pages document only what this repository controls.
 
 `portcullis` is new hardware headed for Nikhef that will take over most of `estuary`'s edge routing.
-It is not deployed yet and the resulting topology is still being worked out.
+It is not deployed yet and the resulting topology is still being worked out. It travels with
+[`fergal`](fergal.md), an OpenWrt SFP+ switch whose firmware this flake builds; both are staged at
+home for now, borrowing the home fabric through
+[jim](../home/switches.md#fergal-portculliss-switch).

docs/sites/colony/fergal.md

@@ -0,0 +1,104 @@
+# fergal
+
+An 8-port SFP+ switch running OpenWrt, bought to sit in front of
+[`portcullis`](portcullis.md) at Nikhef. It is physically at home for now, on the bench alongside
+`portcullis` while that box is staged.
+
+- **Source:** firmware built by this flake — [`openwrt/default.nix`](../../../openwrt/default.nix)
+- **Host:** bare metal
+- **OS:** OpenWrt (snapshot), configured through UCI rather than RouterOS or a UniFi controller
+
+## Hardware
+
+| Component | Inventory |
+|---|---|
+| Platform | XikeStor SKS8300-8X; the board itself is branded ONTi ONT-S508CL-8S |
+| SoC | Realtek RTL9303 (MIPS 34Kc) |
+| Memory | 512 MB |
+| Storage | 32 MiB SPI NOR (`spi0.0`) |
+| Network | 8×SFP+ (`lan1`…`lan8`) |
+
+## Role
+
+`portcullis`'s 10G switch. Nothing else depends on it, and it is not part of the home fabric — it
+is expected to travel to Nikhef with `portcullis` rather than stay behind.
+
+While staged at home it hangs off jim's spare SFP+ port, so `portcullis` can reach the home `hi`
+VLAN over 10G: `lan1` uplinks to jim's `sfp-spare`, `lan2` goes to `portcullis`, and the other six
+cages are empty. See [the home switches](../home/switches.md) for the fabric it borrows.
+
+## Network assignments
+
+fergal has no assignments — it is not managed by the flake. Its management address is
+`192.168.64.30` on the home `core` VLAN, set in UCI as `network.lan`, with no DNS record; reach it
+as `ssh root@192.168.64.30`.
+
+## VLAN configuration
+
+One bridge (`switch`), with VLAN 1 as the untagged PVID on every port — that's the native VLAN on
+jim's `sfp-spare`, and `switch.1` is where fergal's own management address lives. `hi` (100) and
+`lo` (110) are **tagged** members of every port, so a box on any cage can pick them up:
+
+```
+uci show network | grep bridge-vlan
+```
+
+Tagging all eight rather than just `lan1`/`lan2` keeps a spare cage usable without a reconfigure;
+there is nothing sensitive behind it while fergal is on the bench.
+
+**Jumbo frames pass, despite what `ip link` says.** Every DSA port and the `switch` bridge read
+`mtu 1500`, but the RTL9303 forwards between ports in hardware and isn't bound by those — a
+`ping -M do -s 8972` from `portcullis` to the `hi` VIP crosses fergal intact, which is what makes
+the 9000-MTU `hi` VLAN usable over this path. The 1500 does apply to traffic punted to the CPU,
+i.e. fergal's own management on `switch.1`.
+
+## Firmware
+
+The image is built by this flake — see [OpenWrt images](../../deployment.md#openwrt-images) for the
+outputs and the feed pin. Packages are baked into the image, so adding tooling means editing
+[`openwrt/default.nix`](../../../openwrt/default.nix) and reflashing rather than installing on the
+box.
+
+### Flash layout
+
+A single 32 MiB SPI NOR chip (`spi0.0`, 64 KiB erase blocks). `kernel` and `rootfs` are
+sub-partitions of `firmware`, and OpenWrt adds `rootfs_data` as the JFFS2 overlay after a real
+flash.
+
+| Partition | Device | Offset | Size |
+|---|---|---|---|
+| `u-boot` | `mtd0` | `0x000000` | 1 MiB |
+| `board-info` | `mtd1` | `0x100000` | 192 KiB |
+| `syslog` | `mtd2` | `0x130000` | 832 KiB |
+| `firmware` | `mtd3` | `0x200000` | 30 MiB |
+
+**`board-info` is irreplaceable.** It holds the unit's MAC addresses (`[vlanmac]` / `[cpumac]`), its
+`[license]` hash, the stock boot pointers and an SSH host key — only about 1.3 KiB of it is
+non-blank, and none of it can be regenerated. A full dump of all four partitions, taken before
+OpenWrt was flashed, is kept outside this repo — 33 MB of images, with per-partition checksums and
+restore notes. Never write `u-boot` or `board-info` without a confirmed serial/TFTP recovery path.
+
+### Flashing notes
+
+The procedure itself is in [`openwrt-flash.md`](../../openwrt-flash.md); what follows is specific to
+this board.
+
+Stock u-boot boots `flash:/nos.img` from a JFFS2 filesystem, so OpenWrt's sysupgrade image is
+itself a JFFS2 image containing `nos.img` rather than a raw kernel + squashfs. Two things bite when
+flashing from an initramfs, as during the initial install:
+
+- **`sysupgrade -c` does not work.** It needs `/overlay/upper/etc`, which doesn't exist when running
+  from RAM, and it aborts *after* `mtd erase firmware` has already run — leaving the box with no
+  bootable firmware until the job is finished. Pass the config as an explicit tarball instead
+  (`tar czf`, then `sysupgrade -f <tarball> …`).
+- **The working management address may not be in UCI.** If it was set by hand with `ip` while UCI
+  still held the stock address, the box comes back unreachable. Write it into `network.lan` and
+  commit before flashing.
+
+Neither applies to an ordinary flash-to-flash upgrade, where `sysupgrade` keeps `/etc/config` and
+the files listed in `/lib/upgrade/keep.d/` by default. Dropbear host keys are regenerated by a flash
+that doesn't preserve them, so clear the old `known_hosts` entry afterwards.
+
+## Notable config files
+
+- [`openwrt/default.nix`](../../../openwrt/default.nix) — image definition and baked-in package list.

docs/sites/colony/portcullis.md

@@ -28,19 +28,34 @@ this repository covers only what is needed to boot and reach the box.
 
 ## Network assignments
 
-`portcullis` has no static assignments yet. It is being staged at home before it is racked, so it
-takes DHCP on the home `lo` VLAN; the colony assignments land alongside the routing config once the
-topology is decided.
+`portcullis` has no colony assignments yet — those land alongside the routing config once the
+topology is decided. While it is staged at home it holds a single home `hi` assignment, listed in
+[`networking.md#box-assignments`](../../networking.md#box-assignments).
 
 ## Networking
 
 - The four I226-V ports are named `et2g5-0`…`et2g5-3` and the 82599ES SFP+ ports `et10g-0` /
   `et10g-1`, pinned by permanent MAC address in `.link` files.
-- Bootstrap only: a single `.network` matches every `et2g5-*` port and takes DHCP, so whichever
-  port happens to be patched in brings the box up. `wait-online.anyInterface` keeps boot from
-  blocking on the unpatched ports.
-- kea registers the DHCP hostname, so while staged the box answers to `portcullis.dyn.h.nul.ie` —
-  which is also what `my.deploy.node.hostname` points at, since there is no colony FQDN for it yet.
+- Bootstrap: a single `.network` matches every `et2g5-*` port and takes DHCP on the home `lo` VLAN,
+  so whichever port happens to be patched in brings the box up. `wait-online.anyInterface` keeps
+  boot from blocking on the unpatched ports.
+- kea registers the DHCP hostname, so while staged the box also answers to `portcullis.dyn.h.nul.ie`.
+- `my.deploy.node.hostname` is the `hi` address, taken from the assignment rather than written out,
+  since there is no colony FQDN for the box yet.
+
+### 10G to the home `hi` VLAN
+
+`et10g-0` runs over fibre to [`fergal`](fergal.md), which uplinks to jim's `sfp-spare` port. That
+uplink is untagged VLAN 1, so `hi` is carried tagged on a `lan-hi` VLAN interface rather than on the
+port itself; the physical link takes the `hi` jumbo MTU so the whole path is consistent with the
+rest of the VLAN. `lan-hi` carries the static assignment, resolves through the router VIPs like
+every other `hi` client, and its gateway route outranks the DHCP default, so the 10G path is
+preferred while the 2.5G one stays as a fallback.
+
+Both jim and `fergal` tag `hi` and `lo` along that path. It exists only while the box is staged at
+home — `fergal` goes to Nikhef with it.
+
+The other SFP+ port, `et10g-1`, is unused.
 
 ## Storage
 

docs/sites/home/switches.md

@@ -11,7 +11,8 @@ carried untranslated because a single ONT makes it unique on the fabric — see
 [the WAN path](#the-digiweb-wan-path-trunked-vlan-10--pvid-140) and
 [why not translation](#why-not-translation-for-one-ont). The router side lives in
 [river.md](river.md); the logical network map in [networking.md](../../networking.md). The Wi-Fi
-APs that hang off these switches are in [aps.md](aps.md).
+APs that hang off these switches are in [aps.md](aps.md). A fourth switch, **fergal**, hangs off jim
+but belongs to the colony site — see [fergal](#fergal-portculliss-switch).
 
 ## The switches
 
@@ -34,13 +35,14 @@ chips); brian cannot rewrite tags, only trunk/PVID them.
 The two WAN sources enter at the top: the Virgin Media modem lands on **jim** (VLAN 130), and the
 Digiweb **ONT** lands on **brian**. Both `jim` and `brian` are edge switches that uplink down into
 the **dave** core; the home boxes hang off dave's 100G ports, with backup links up to jim. jim's
-`wan-pon-in` (`sfp-sfpplus2`) is a spare SFP+ port, unused today.
+second SFP+ port (`sfp-spare`, `sfp-sfpplus2`) feeds [fergal](#fergal-portculliss-switch), which
+[`portcullis`](../colony/portcullis.md) hangs off while it is staged at home.
 
 ```
   Virgin Media cable modem                         Digiweb ONT
   stream WAN, VLAN 130                             river WAN, management + VLAN 10
              |                                               |
-            jim                                            brian
+            jim ---- 10G ---- fergal ---- portcullis         brian
              | 10G trunk                         802.3ad LAG |
              +--------------------+          +---------------+
                                   |          |
@@ -146,8 +148,13 @@ VLAN 140 also spans `brian-downlink,palace` (it carries a few other members too)
 this is plain tagged bridging.
 
 **jim (RouterOS)** — carries **none** of the Digiweb WAN path: no translation rules, and no VLAN
-10/140/141 rows. `wan-pon-in` (`sfp-sfpplus2`) sits at `pvid=1` as a spare port. jim only handles
-stream's VLAN-130 WAN and the LAN VLANs.
+10/140/141 rows. jim only handles stream's VLAN-130 WAN and the LAN VLANs. `sfp-spare`
+(`sfp-sfpplus2`) stays at `pvid=1` — the switch feeding `portcullis` is reached over VLAN 1
+untagged — and is a **tagged** member of `hi` (100) and `lo` (110) so those reach `portcullis`:
+```
+/interface bridge vlan set [find bridge=main vlan-ids=100] tagged=...,sfp-spare
+/interface bridge vlan set [find bridge=main vlan-ids=110] tagged=...,sfp-spare
+```
 
 ## Switches must not route
 
@@ -200,11 +207,22 @@ Each ONT port must also be a tagged member of bridge VLAN 10 for correct egress
 piece that otherwise shows up as pppd "Timeout waiting for PADO"). The pins bypass the FDB, so the
 two ISP sessions never mix.
 
-**Why a new switch:** jim (the only box with spare SFP+ *and* the translation feature) has just
-**one** free SFP+ port, so it can't host two ONTs. The plan is a dedicated
+**Why a new switch:** jim (the only box with spare SFP+ *and* the translation feature) had just
+**one** free SFP+ port — now taken by fergal — so it can't host two ONTs. The plan is a dedicated
 **CRS305-1G-4S+** (4×SFP+, same Marvell rule support) to land multiple ONTs and do the per-port
 translation there, feeding distinct fabric VLANs up to dave.
 
+## fergal (portcullis's switch)
+
+**fergal** is an 8-port SFP+ switch running OpenWrt, hanging off jim's `sfp-spare` port. It belongs
+to [`portcullis`](../colony/portcullis.md) rather than to the home fabric — it is here only while
+that box is staged at home, and goes to Nikhef with it. Nothing in the home fabric depends on it.
+
+What it borrows from home is VLAN 1 untagged on the jim uplink (fergal's own management sits on it,
+at `192.168.64.30` on core) plus tagged `hi` (100) and `lo` (110), so `portcullis` can reach those
+over 10G. The switch itself — VLAN layout, flash layout, firmware and flashing notes — is
+documented in [sites/colony/fergal.md](../colony/fergal.md).
+
 ## Accessing the switches
 
 The switches resolve by **short hostname** on the home network — the home routers serve their

flake.lock

@@ -8,7 +8,7 @@
           "ragenix",
           "nixpkgs"
         ],
-        "systems": "systems_7"
+        "systems": "systems_8"
       },
       "locked": {
         "lastModified": 1761656077,
@@ -315,6 +315,27 @@
         "url": "https://flakehub.com/f/hercules-ci/flake-parts/0.1"
       }
     },
+    "flake-parts_2": {
+      "inputs": {
+        "nixpkgs-lib": [
+          "openwrt-imagebuilder",
+          "nixpkgs"
+        ]
+      },
+      "locked": {
+        "lastModified": 1772408722,
+        "narHash": "sha256-rHuJtdcOjK7rAHpHphUb1iCvgkU3GpfvicLMwwnfMT0=",
+        "owner": "hercules-ci",
+        "repo": "flake-parts",
+        "rev": "f20dc5d9b8027381c474144ecabc9034d6a839a3",
+        "type": "github"
+      },
+      "original": {
+        "owner": "hercules-ci",
+        "repo": "flake-parts",
+        "type": "github"
+      }
+    },
     "flake-utils": {
       "inputs": {
         "systems": "systems"
@@ -335,7 +356,7 @@
     },
     "flake-utils_10": {
       "inputs": {
-        "systems": "systems_9"
+        "systems": "systems_10"
       },
       "locked": {
         "lastModified": 1709126324,
@@ -353,7 +374,7 @@
     },
     "flake-utils_11": {
       "inputs": {
-        "systems": "systems_10"
+        "systems": "systems_11"
       },
       "locked": {
         "lastModified": 1705309234,
@@ -503,7 +524,7 @@
     },
     "flake-utils_9": {
       "inputs": {
-        "systems": "systems_8"
+        "systems": "systems_9"
       },
       "locked": {
         "lastModified": 1731533236,
@@ -910,6 +931,51 @@
         "type": "github"
       }
     },
+    "openwrt-feeds": {
+      "inputs": {
+        "nixpkgs": [
+          "nixpkgs-unstable"
+        ],
+        "openwrt-imagebuilder": [
+          "openwrt-imagebuilder"
+        ]
+      },
+      "locked": {
+        "lastModified": 1787353688,
+        "narHash": "sha256-YDEm+ev3BpDS9Sq1ByVv0i5QQCE1yezpjWVhcNBBjCE=",
+        "owner": "devplayer0",
+        "repo": "openwrt-feeds",
+        "rev": "a30b2b5f83c7d1fffca2146453e8d5866b882da4",
+        "type": "github"
+      },
+      "original": {
+        "owner": "devplayer0",
+        "repo": "openwrt-feeds",
+        "type": "github"
+      }
+    },
+    "openwrt-imagebuilder": {
+      "inputs": {
+        "flake-parts": "flake-parts_2",
+        "nixpkgs": [
+          "nixpkgs-unstable"
+        ],
+        "systems": "systems_7"
+      },
+      "locked": {
+        "lastModified": 1787302424,
+        "narHash": "sha256-fg9pKzO6OeQhe/bY2CpHb6QnHq57P/icwQz35GF/R/8=",
+        "owner": "astro",
+        "repo": "nix-openwrt-imagebuilder",
+        "rev": "276c1dd6346f50231392e97b3a9987c9dd57da28",
+        "type": "github"
+      },
+      "original": {
+        "owner": "astro",
+        "repo": "nix-openwrt-imagebuilder",
+        "type": "github"
+      }
+    },
     "pyproject-nix": {
       "inputs": {
         "nixpkgs": [
@@ -976,6 +1042,8 @@
         "nixpkgs-mine-stable": "nixpkgs-mine-stable",
         "nixpkgs-stable": "nixpkgs-stable",
         "nixpkgs-unstable": "nixpkgs-unstable",
+        "openwrt-feeds": "openwrt-feeds",
+        "openwrt-imagebuilder": "openwrt-imagebuilder",
         "ragenix": "ragenix",
         "sharry": "sharry"
       }
@@ -1073,6 +1141,21 @@
         "type": "github"
       }
     },
+    "systems_11": {
+      "locked": {
+        "lastModified": 1681028828,
+        "narHash": "sha256-Vy1rq5AaRuLzOxct8nz4T6wlgyUR7zLU309k9mBC768=",
+        "owner": "nix-systems",
+        "repo": "default",
+        "rev": "da67096a3b9bf56a91d16901293e51ba5b49a27e",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-systems",
+        "repo": "default",
+        "type": "github"
+      }
+    },
     "systems_2": {
       "locked": {
         "lastModified": 1681028828,
@@ -1150,16 +1233,16 @@
     },
     "systems_7": {
       "locked": {
-        "lastModified": 1681028828,
-        "narHash": "sha256-Vy1rq5AaRuLzOxct8nz4T6wlgyUR7zLU309k9mBC768=",
+        "lastModified": 1680978846,
+        "narHash": "sha256-Gtqg8b/v49BFDpDetjclCYXm8mAnTrUzR0JnE2nv5aw=",
         "owner": "nix-systems",
-        "repo": "default",
-        "rev": "da67096a3b9bf56a91d16901293e51ba5b49a27e",
+        "repo": "x86_64-linux",
+        "rev": "2ecfcac5e15790ba6ce360ceccddb15ad16d08a8",
         "type": "github"
       },
       "original": {
         "owner": "nix-systems",
-        "repo": "default",
+        "repo": "x86_64-linux",
         "type": "github"
       }
     },

flake.nix

@@ -58,6 +58,15 @@
     # harmonia.url = "github:devplayer0/harmonia/cache-config-daemon-store";
     harmonia.inputs.nixpkgs.follows = "nixpkgs-unstable";
 
+    # Firmware building for the OpenWrt boxes, which aren't managed by this flake otherwise.
+    # `openwrt-feeds` pins the package feeds; without it, evaluation would reach the OpenWrt
+    # download server over import-from-derivation and break on hashes that upstream rotates daily.
+    openwrt-imagebuilder.url = "github:astro/nix-openwrt-imagebuilder";
+    openwrt-imagebuilder.inputs.nixpkgs.follows = "nixpkgs-unstable";
+    openwrt-feeds.url = "github:devplayer0/openwrt-feeds";
+    openwrt-feeds.inputs.nixpkgs.follows = "nixpkgs-unstable";
+    openwrt-feeds.inputs.openwrt-imagebuilder.follows = "openwrt-imagebuilder";
+
     # Packages not in nixpkgs
     sharry.url = "github:eikek/sharry";
     sharry.inputs.nixpkgs.follows = "nixpkgs-unstable";
@@ -259,7 +268,9 @@
         deploy = recurseIntoAttrs (pkgs.deploy-rs.lib.deployChecks self.deploy);
       };
 
-      packages = flattenTree (import ./pkgs { inherit lib pkgs; });
+      packages = flattenTree (
+        (import ./pkgs { inherit lib pkgs; }) //
+        (import ./openwrt { inherit pkgs inputs; }));
 
       devShells.default = shell;
 

nixos/boxes/colony/portcullis/default.nix

@@ -1,6 +1,8 @@
 { lib, ... }:
 let
+  inherit (lib.my) net;
   inherit (lib.my.c.colony) domain;
+  home = lib.my.c.home;
 in
 {
   nixos.systems.portcullis = {
@@ -8,7 +10,29 @@ in
     nixpkgs = "mine-stable";
     home-manager = "mine-stable";
 
-    configuration = { lib, pkgs, config, ... }:
+    assignments = {
+      # Staging-only: the 10G link lands on the home hi VLAN until portcullis is racked.
+      hi = {
+        domain = home.domain;
+        mtu = home.hiMTU;
+        ipv4 = {
+          address = net.cidr.host 41 home.prefixes.hi.v4;
+          mask = 22;
+          gateway = home.vips.hi.v4;
+        };
+        ipv6 = {
+          iid = "::6:1";
+          address = net.cidr.host (65536*6+1) home.prefixes.hi.v6;
+        };
+      };
+    };
+
+    configuration = { lib, pkgs, config, assignments, ... }:
+      let
+        inherit (lib) mkMerge;
+        inherit (lib.my) mkVLAN networkdAssignment;
+        inherit (lib.my.c) networkd;
+      in
       {
         hardware = {
           enableRedistributableFirmware = true;
@@ -54,10 +78,12 @@ in
         ];
 
         systemd.network = {
-          # Only one port is patched in while the box is being staged, so don't block
+          # Only some ports are patched in while the box is being staged, so don't block
           # boot on the others coming up.
           wait-online.anyInterface = true;
 
+          netdevs = mkVLAN "lan-hi" home.vlans.hi;
+
           links = {
             "10-et2g5-0" = {
               matchConfig.PermanentMACAddress = "00:d0:b4:05:ed:48";
@@ -88,8 +114,8 @@ in
 
           networks = {
             # TODO: replace with the colony assignments and routing config once portcullis is
-            # racked at Nikhef. Until then it is staged on the home lo VLAN, so every 2.5G port
-            # takes DHCP and whichever one is patched in provides connectivity. kea registers
+            # racked at Nikhef. Until then it is staged at home, so every 2.5G port takes DHCP on
+            # the lo VLAN and whichever one is patched in provides connectivity. kea registers
             # the DHCP hostname, making the box reachable as `portcullis.dyn.h.nul.ie`.
             "80-bootstrap" = {
               matchConfig.Name = "et2g5-*";
@@ -97,12 +123,29 @@ in
               networkConfig.IPv6PrivacyExtensions = "no";
               linkConfig.RequiredForOnline = "routable";
             };
+
+            # 10G up to jim's spare SFP+ port via an intermediary switch. That uplink is
+            # untagged VLAN 1, so hi has to be tagged on its own interface.
+            "81-et10g-0" = {
+              matchConfig.Name = "et10g-0";
+              vlan = [ "lan-hi" ];
+              networkConfig = networkd.noL3;
+              linkConfig = {
+                # The carrier has to allow hi's jumbo frames before lan-hi can take that MTU
+                MTUBytes = toString home.hiMTU;
+                RequiredForOnline = "no";
+              };
+            };
+            "82-lan-hi" = mkMerge [
+              (networkdAssignment "lan-hi" assignments.hi)
+              { networkConfig = home.vlanDns "hi"; }
+            ];
           };
         };
 
         my = {
-          # As above: no colony assignment yet, so point deploy at the staging DHCP name.
-          deploy.node.hostname = "portcullis.dyn.${lib.my.c.home.domain}";
+          # As above: no colony assignment yet, so deploy over the staging hi address.
+          deploy.node.hostname = assignments.hi.ipv4.address;
 
           secrets = {
             key = "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIAUolR93Byg+Daw8pUYHVpQ34ioxSc2C8vzj9F4KbqMs";

openwrt/default.nix

@@ -0,0 +1,32 @@
+{ pkgs, inputs }:
+# Firmware for the OpenWrt boxes. They are not NixOS and are not deployed by this flake - these
+# outputs only build a sysupgrade image, which is then flashed by hand (see the box's docs page).
+#
+# Baking packages into the image is the only reliable way to have them: OpenWrt's package server
+# keeps just the current build of each feed, so a box installing packages at runtime is broken as
+# soon as the feed moves on from the firmware it is running.
+let
+  inherit (inputs) openwrt-imagebuilder openwrt-feeds;
+
+  # Fallback to the release branch. Snapshot tracks OpenWrt main, which is where the rtl930x target
+  # is actually being developed; the release runs a much older kernel. Both are pinned by
+  # `openwrt-feeds`, so neither moves until that input is updated.
+  release = "25.12.5";
+
+  mkImage = args: openwrt-imagebuilder.lib.build (args // {
+    inherit pkgs;
+    cachePath = openwrt-feeds.cachePaths.${args.release};
+  });
+
+  # fergal, the 8-port SFP+ switch (XikeStor SKS8300-8X, board-branded ONTi ONT-S508CL-8S)
+  fergal = {
+    target = "realtek";
+    variant = "rtl930x";
+    profile = "xikestor_sks8300-8x";
+    packages = [ "luci" "ip-full" "ip-bridge" "ethtool-full" "luci-app-sfp-info" ];
+  };
+in
+{
+  openwrt-fergal = mkImage (fergal // { release = "snapshot"; });
+  openwrt-fergal-release = mkImage (fergal // { inherit release; });
+}