cat << '_EOF_' > /root/reboot-on-missing-wifi.sh
#!/bin/dash
if [ -e '/sys/class/net/wlan0' ]
then
echo 'OK: wlan0 interface exists, proceeding with boot'
rm -f /root/reboot-on-missing-wifi.flag
elif [ -e '/root/reboot-on-missing-wifi.flag' ]
then
echo 'FAILED: Reboot has been done already, but wlan0 interface is still missing!'
else
echo 'PENDING: wlan0 interface does not exist, creating flag and doing reboot'
> /root/reboot-on-missing-wifi.flag
reboot
exit 0
fi
_EOF_
chmod +x /root/reboot-on-missing-wifi.sh
cat << '_EOF_' > /etc/systemd/system/reboot-on-missing-wifi.service
[Unit]
Description=Reboot on missing WiFi
DefaultDependencies=no
After=systemd-remount-fs.service -.mount
Wants=local-fs-pre.target
Before=local-fs-pre.target
[Service]
Type=oneshot
StandardOutput=file:/root/reboot-on-missing-wifi.log
ExecStart=/root/reboot-on-missing-wifi.sh
[Install]
WantedBy=local-fs.target
_EOF_
systemctl daemon-reload
systemctl enable reboot-on-missing-wifi
At early boot, just after the rootfs has been mounted R/W, it checks whether the wlan0 interface exists, and does a reboot if not. It also creates a flag file, and does not reboot anymore if this exists already but the interface is still missing. The flag is removed once the interface exists.
I had a look on Armbian : they have now a community build for R5C. It works fine and wlan0 is present, but there is still the problem to build the module. The headers are installed OK by armbian-config, but if I want to build, I get a missing “build” file. So I install linux 6.6.31 from kernel.org and build OK.
But when I want to build the module I get the traditional error about symvers missing.
With dietpi the building of the module was immediate, it worked at first try.
I used dash (bourne shell) intentionally, being a bit faster. I hope I did not accidentally left bash syntax inside. However, using bash will of course work as well.
Great that it works. It currently appends a log entry to /root/reboot-on-missing-wifi.log on every (re)boot. Good to monitor for some (re)boots to see whether it works reliably. Afterwards, you could remove the StandardOutput line from /etc/systemd/system/reboot-on-missing-wifi.service to disable file logging. You can then still see the last entry via:
journalctl -u reboot-on-missing-wifi
That one should match exactly our kernel+bootloader and there was no recent related commit. Are you sure it works consistently on cold boots? The first boot of Armbian AFAIK includes a reboot, after partition/filesystem expansion, so that would not count.
I guess it is just the symlink missing or revised:
Not sure how you installed Linux 6.6.31, but there are quite a few things to take care of, including all the symlinks in /boot. So I would not recommend that, unless you know well how the Armbian bootloader and scripts work, i.e. which files/dirs they are looking for etc.
Sorry, I did not know dash.
Armbian : you are right, it worked first time because of the reboot (I did not notice that), but after that, it has the same problem : wlan0 not present on cold boots, only on reboot, no difference.
About 6.6.31 : I just used the armbian-config menu which allows to choose different kernels, as I experienced in the past that it installs the proper headers. This is just for infomation, because Armbian is not interesting if the WiFi problem is the same.
About R5S / R5C, the last images of Dietpi work very well (with the limit of the discussion above for R5C). I was able to compile an app with the headers present. But now I must compile a kernel module, and this requires additional stuff, because the system complains about the missing /lib/modules/6.6.32-current-rockchip64/build.
Where can I find the kernel files necessary to compile a kernel module ? I prefer to ask you, because you will know what are the proper files.
If you can switch images I‘d recommend you to switch to the Armbian built ones as they’re a better “dev environment” and have proper repo‘s for all the kernel related stuff. (I use it myself at this point)
The DietPi image should also be based on their builder (not sure what the update interval is) but I‘m not sure if updates etc. are also in sync with their system on DietPi.
I checked with Armbian, but the problem is exactly the same :
make[1]: *** /lib/modules/6.6.32-current-rockchip64/build : no file or directory of this type. Halt.
To create this “build” directory, I need the kernel files for 6.6.31-current-rockchip64. But Armbian does not give them (or at least I didn’t find). I tried to use armbian-config to change to 6.6.35 (6.6.32 is not offered), same problem. The kernel files are not offered, only the modules, overlays and headers. They are installed by the .deb file found here : https://mirrors.dotsrc.org/armbian-apt/pool/main/l/linux-6.6.32/
So, I came back to Dietpi and tried to get the 6.6.32 from kernel.org. It was then possible to build the module, but when I want to install it I get the error :
tlsfilter: version magic '6.6.32 SMP preempt mod_unload aarch64' should be '6.6.32-current-rockchip64 SMP preempt mod_unload aarch64'
insmod: ERROR: could not insert module tlsfilter.ko: invalide module format.
So I really need the kernel files 6.6.32-current-rockchip64, but I find them nowhere.
What I do to create the build directory is just :
Copy the config file from boot to the kernel files directory
make oldconfig
make modules_prepare
then in the module directory : make -C ~/kernel/linux-6.6.32
You can clone armbian/build from Github. While the 6.6 kernel is the upstream one Armbian applies some patches onto it. With the armbian/build tool you can download and compile the kernel source that you need
Good evening Dysmas,
the kernel headers can be installed with:
apt install linux-headers-current-rockchip64
Best regards,
Micha (aka MichaIng)
DietPi project lead
Simple, and it worked. After that install, the module built without problem.
But thank you for your answers, nevertheless, meco, it was kind of you.