Write up the onboard WiFi investigation, and ship the services it needs

aarch64-laptops' support table ticks WiFi for this machine, so the path exists.
Following their WiFi README got considerably further and then stopped somewhere
useful to have documented.

Two of the four services they list are in the kernel now (pd-mapper, qrtr-ns).
The other two, rmtfs and tqftpserv, are packaged in Fedora and shipped
disabled — tqftpserv was not even installed. Both are now in base.pkgs and
enabled by stage2. Enabling them took qrtr-lookup from 19 registered services
to 25; a working setup is said to show around 40.

The step worth having written down: the modem does not read wlanmdsp.mbn from
/lib/firmware. It asks tqftpserv for it over TFTP, from
/lib/firmware/readonly/firmware/image/. Nothing reports this as an error —
ath10k_snoc binds, registers a QMI client, and waits forever for a service that
never registers. c630-firmware now places the file there, and creates the
writable area the modem asks tqftpserv for.

Where it stops: the modem boots and dies at "RF stuck in QLINK start state",
about every 42 seconds, never reaching the point of requesting wlanmdsp. Three
firmware pairings give three distinct failures, recorded in the doc — the _nm
"no modem" variants, which are the obvious idea and would skip cellular RF
entirely, turn out not to be signed for this device.

The result that narrows it: aarch64-laptops' own wifi directory carries the
qcdsp1v2850.mbn, qcdsp2850.mbn and wlanmdsp.mbn from the setup whose table ticks
WiFi. All three differ from the WOA-Project copies. Installed here with the
services running and wlanmdsp in the TFTP path, they produce the identical QLINK
failure — so it is neither the firmware nor the userspace. What is left is the
kernel: 5.x from 2019 there against 7.1.5 here, with both of their ath10k
patches long since upstream. That points at a regression, and confirming it
means a bisect rather than another file.

Also record what is untried: the other eight driver versions (this machine's
UEFI is from 2019 and the newest package may be the wrong vintage),
mcfg_subsys_ext850.cab, and building board-2.bin from the C630's own bdwlan.*
files.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01XWRjNJMistCy6ngXH5aJLS

build/stage2.sh

@@ -278,11 +278,17 @@ echo "${DEFAULT_USER}:${DEFAULT_PASSWORD}" | chroot "$ROOTFS" chpasswd
 chroot "$ROOTFS" chage -d 0 "$DEFAULT_USER"   # force a change at first login
 chroot "$ROOTFS" passwd -l root
 
+# rmtfs and tqftpserv are both shipped disabled by Fedora. They are inert
+# without modem firmware and cost nothing to have running, so enable them here
+# rather than leaving a step to rediscover later — onboard WiFi cannot work
+# without tqftpserv, since the modem fetches the WLAN firmware over TFTP.
 chroot "$ROOTFS" systemctl enable \
     c630-growfs.service \
     sshd.service \
     NetworkManager.service \
-    systemd-resolved.service
+    systemd-resolved.service \
+    rmtfs.service \
+    tqftpserv.service
 
 if [ "$VARIANT" = workstation ]; then
     chroot "$ROOTFS" systemctl set-default graphical.target

config/packages/base.pkgs

@@ -28,6 +28,16 @@ atheros-firmware
 # partition. See docs/firmware.md — those cannot be redistributed.
 qcom-firmware-extract
 
+# The modem has no storage of its own. rmtfs serves it the NV and calibration
+# partitions (modemst1/2, fsg, fsc); tqftpserv serves it files over TFTP,
+# including the WLAN firmware, which is why onboard WiFi depends on it. The
+# other two services aarch64-laptops lists — pd-mapper and qrtr-ns — are in the
+# kernel now. qrtr is here for qrtr-lookup, which is how you see whether the
+# modem has registered its QMI services. See docs/firmware.md.
+rmtfs
+tqftpserv
+qrtr
+
 # --- boot ---------------------------------------------------------------
 grub2-efi-aa64
 grub2-efi-aa64-modules

docs/firmware.md

@@ -199,15 +199,75 @@ Whichever route, drop the result into `firmware/local/` and rebuild — see
 Installing all of it still leaves two things broken, both for reasons that are
 not about firmware. Recorded here so nobody repeats the search.
 
-### Onboard WiFi needs the modem, and the modem needs firmware nobody publishes
+### Onboard WiFi: everything is in place except a working modem
 
 The name gives it away: **wlan*mdsp*** is the WLAN *Modem* DSP. On SDM845 the
-WiFi firmware is loaded by the modem subsystem, so `ath10k_snoc` binds to
-`18800000.wifi` and then sits silent, waiting on a QMI service that only appears
-once the modem is up. It never logs an error, because from its point of view
-nothing has gone wrong yet.
+WiFi firmware runs on the modem, so `ath10k_snoc` binds to `18800000.wifi` and
+then sits silent. It logs nothing and fails nothing — it has registered a QMI
+client and is waiting for service 69, `wlfw`, which only appears once the modem
+is up. `qrtr-lookup` shows what is and is not there.
 
-The modem itself boots and then dies:
+Everything on the WiFi side checks out:
+
+- `ath10k_snoc` binds successfully and is not in deferred probe
+- the device tree carries `qcom,calibration-variant = "Lenovo_C630"`
+- Fedora's `board-2.bin` contains a matching `variant=Lenovo_C630` entry
+- `modemst1` and `modemst2` hold ~2 MB of real NV data — not wiped
+
+#### The userspace services are required, and mostly missing by default
+
+[aarch64-laptops' WiFi README][aal-wifi] lists four services. On a current
+Fedora two of them are now in the kernel, and the other two are packaged but
+inactive:
+
+| Service | Status here |
+|---|---|
+| `pd-mapper` | in-kernel as `qcom_pd_mapper` — nothing to install |
+| `qrtr-ns` | in-kernel — the `qrtr` package supplies only `qrtr-lookup`/`qrtr-cfg` |
+| `rmtfs` | packaged, **disabled by default** — serves the modem's NV partitions |
+| `tqftpserv` | packaged, **not installed** — serves files to the modem over TFTP |
+
+```sh
+sudo dnf install rmtfs tqftpserv qrtr
+sudo systemctl enable --now rmtfs tqftpserv
+```
+
+Enabling these took `qrtr-lookup` from 19 services to 25. A working setup is
+said to show around 40.
+
+[aal-wifi]: https://github.com/aarch64-laptops/build/tree/master/misc/lenovo-yoga-c630/wifi
+
+#### The modem fetches wlanmdsp over TFTP
+
+This is the step that is easy to miss, and the reason `tqftpserv` exists.
+`tqftpserv` serves from `/lib/firmware/`, and the modem asks it for the WLAN
+firmware by path:
+
+```sh
+sudo mkdir -p /lib/firmware/readonly/firmware/image
+sudo cp wlanmdsp.mbn /lib/firmware/readonly/firmware/image/
+```
+
+The modem also wants a writable area, and says so in the `tqftpserv` journal:
+
+```
+[TQFTP] RRQ: /readwrite/ota_firewall/ruleset → unable to open (2), reject
+[TQFTP] WRQ: /readwrite/server_check.txt
+```
+
+```sh
+sudo mkdir -p /lib/firmware/readwrite/ota_firewall
+sudo touch /lib/firmware/readwrite/ota_firewall/ruleset
+sudo chmod -R 0777 /lib/firmware/readwrite
+```
+
+Watching `journalctl -u tqftpserv` while starting the modem is the best
+available feedback channel — it shows exactly which paths the modem wants.
+
+#### Where it actually stops
+
+The modem boots and then dies at RF front-end initialisation, roughly every 42
+seconds until stopped:
 
 ```
 qcom-q6v5-mss 4080000.remoteproc: MBA booted without debug policy, loading mpss
@@ -216,32 +276,54 @@ qcom-q6v5-mss 4080000.remoteproc: fatal error received:
 remoteproc remoteproc0: crash detected ... recovering
 ```
 
-QLINK is the RF front-end interface. Why it hangs is **not established**. The
-machine has a SIM slot and its modem worked under Windows, so the radio hardware
-is present and functional — this is not a WiFi-only SKU. Candidates worth
-investigating: a version mismatch between these images and what the device's
-TrustZone or boot chain expects, missing calibration data the modem cannot
-reach, or a kernel-side gap. It restarts about every 42 seconds until stopped.
+It never gets far enough to request `wlanmdsp`, so WLAN never starts.
 
-Note the same cabinets supply the GPU, DSP and venus firmware, all of which
-work. Whatever is wrong is specific to the modem.
+Three firmware pairings, three distinct failures — worth recording, because the
+differences are informative:
+
+| MBA (stage 1) | mpss (stage 2) | Result |
+|---|---|---|
+| full | full | boots, dies at `RF stuck in QLINK start state` |
+| `_nm` | `_nm` | `PBL returned unexpected status` — rejected by the boot ROM |
+| full | `_nm` | `MPSS header authentication failed: -3` |
+
+The `_nm` ("no modem") variants are the obvious idea — Fedora ships the
+equivalent `modem_nm.mbn` for generic sdm845, and skipping cellular RF is
+exactly what is wanted here. They are not signed for this device and cannot be
+made to load.
+
+#### Firmware has been eliminated as the variable
+
+The decisive test: [aarch64-laptops' wifi directory][aal-wifi] contains the
+`qcdsp1v2850.mbn`, `qcdsp2850.mbn` and `wlanmdsp.mbn` from the setup whose
+support table ticks WiFi. All three differ from the WOA-Project copies — the
+modem pair matches on size but not checksum. Installed on this machine, with
+`rmtfs` and `tqftpserv` running and `wlanmdsp` in the TFTP path, they produce
+the **identical** QLINK failure.
+
+So the difference is not the firmware, and not the userspace services. What
+remains is the kernel: that setup ran `aarch64-laptops/linux` branch `gpu`,
+circa 2019 on 5.x, against 7.1.5 here. Both ath10k patches it applied are long
+upstream — the device tree carries `qcom,snoc-host-cap-8bit-quirk` from the
+first of them. Six years of `qcom-q6v5-mss` churn sits between the two.
+
+That points at a kernel regression rather than anything missing on disk.
+Confirming it means bisecting or booting an older kernel, which nothing here
+does yet.
 
 Things that sound like they should help and do not:
 
-- **`rmtfs`.** The modem stores its NV and calibration on the `modemst1`,
-  `modemst2`, `fsg` and `fsc` partitions and reaches them through the `rmtfs`
-  daemon. Fedora packages it, and it is disabled by default. Enabling it is
-  correct and worth doing — `sudo systemctl enable --now rmtfs` — but the QLINK
-  failure persists with it running. Its "failed to update start state" warnings
-  are its optional remoteproc-control helper and are harmless.
-- **The `_nm` firmware variants.** `qcdsp1v2850_nm.mbn` and `qcdsp2850_nm.mbn`
-  are the no-modem images, 5.7 MB against 60 MB, analogous to the `modem_nm.mbn`
-  Fedora ships for generic sdm845. They are rejected before they even run:
-  `PBL returned unexpected status`.
-- **Unplugging the USB WiFi dongle.** Different bus, different driver, no
-  interaction. `ath10k_snoc` is waiting on the modem, not competing for a radio.
+- **Unplugging the USB WiFi dongle.** Different bus, different driver.
+  `ath10k_snoc` is waiting on the modem, not competing for a radio.
+- **`rmtfs` alone.** Necessary, not sufficient. Its "failed to update start
+  state" warnings are its optional remoteproc-control helper and are harmless.
+- **The `_nm` variants.** See above.
 
-A USB dongle or USB tethering from a phone is the practical answer.
+Untried, in rough order of promise: the other eight driver versions under
+`Lenovo/YogaC630/` (this machine's UEFI is `9UCN33WW(V2.06)` from 2019, and the
+newest package may not be the right vintage); `mcfg_subsys_ext850.cab`, which
+holds modem configuration data; and building `board-2.bin` from the C630's own
+`bdwlan.*` files rather than relying on Fedora's.
 
 ### Audio is a kernel driver problem
 

overlay/usr/local/sbin/c630-firmware

@@ -49,6 +49,20 @@ if [ -f "${FW_DIR}/qcdxkmsuc850.mbn" ]; then
     echo "GPU zap shader will be included in the initramfs."
 fi
 
+# The modem does not read wlanmdsp.mbn from /lib/firmware directly — it asks
+# tqftpserv for it by path. Without this, onboard WiFi cannot start even with
+# every other file in place, and nothing says so: ath10k_snoc simply waits
+# forever for a QMI service that never registers. It also wants somewhere
+# writable. See docs/firmware.md.
+if [ -f "${FW_DIR}/wlanmdsp.mbn" ]; then
+    install -D -o root -g root -m 644 \
+        "${FW_DIR}/wlanmdsp.mbn" /lib/firmware/readonly/firmware/image/wlanmdsp.mbn
+    mkdir -p /lib/firmware/readwrite/ota_firewall
+    : > /lib/firmware/readwrite/ota_firewall/ruleset
+    chmod -R 0777 /lib/firmware/readwrite
+    echo "Placed wlanmdsp.mbn where tqftpserv will serve it to the modem."
+fi
+
 echo "Regenerating the initramfs..."
 dracut --force --regenerate-all