Sample files to enable wireless on Debian initramfs

a_enable_wireless.sh

#!/bin/sh
# this goes into /etc/initramfs-tools/scripts/init-premount/a_enable_wireless
PREREQ=""
prereqs()
{
    echo "$PREREQ"
}

case $1 in
prereqs)
    prereqs
    exit 0
    ;;
esac

. /scripts/functions

AUTH_LIMIT=30
INTERFACE="wlp5s0"
alias WPACLI="/sbin/wpa_cli -p/tmp/wpa_supplicant -i$INTERFACE "

log_begin_msg "Starting WLAN connection"
/sbin/wpa_supplicant  -i$INTERFACE -c/etc/wpa_supplicant.conf -P/run/initram-wpa_supplicant.pid -B -f /tmp/wpa_supplicant.log

# Wait for AUTH_LIMIT seconds, then check the status
limit=${AUTH_LIMIT}

echo -n "Waiting for connection (max ${AUTH_LIMIT} seconds)"
while [ $limit -ge 0 -a `WPACLI status | grep wpa_state` != "wpa_state=COMPLETED" ]
do
    sleep 1
    echo -n "."
    limit=`expr $limit - 1`
done
echo ""

if [ `WPACLI status | grep wpa_state` != "wpa_state=COMPLETED" ]; then
  ONLINE=0
  log_failure_msg "WLAN offline after timeout"
  panic
else
  ONLINE=1
  log_success_msg "WLAN online"
fi

configure_networking

enable-wireless.sh

# !/bin/sh
# This goes into /etc/initramfs-tools/hooks/enable-wireless
set -e
PREREQ=""
prereqs()
{
    echo "${PREREQ}"
}
case "${1}" in
    prereqs)
        prereqs
        exit 0
        ;;
esac

. /usr/share/initramfs-tools/hook-functions

# CHANGE HERE for your correct modules.
manual_add_modules iwlwifi iwlmvm
copy_exec /sbin/wpa_supplicant
copy_exec /sbin/wpa_cli
copy_file config /etc/initramfs-tools/wpa_supplicant.conf /etc/wpa_supplicant.conf

final_commands.sh

# This is run on the shell
chmod +x /etc/initramfs-tools/scripts/local-bottom/kill_wireless
chmod +x /etc/initramfs-tools/scripts/init-premount/a_enable_wireless
chmod +x /etc/initramfs-tools/hooks/enable-wireless

update-initramfs -k all -u
update-grub

kill_wireless.sh

#!/bin/sh
# this goes into /etc/initramfs-tools/scripts/local-bottom/kill_wireless
PREREQ=""
prereqs()
{
    echo "$PREREQ"
}

case $1 in
prereqs)
    prereqs
    exit 0
    ;;
esac

echo "Killing wpa_supplicant so the system takes over later."
kill `cat /run/initram-wpa_supplicant.pid`

wpa_supplicant.conf

# sample /etc/initramfs-tools/wpa_supplicant.conf
# note that this is independent of the system /etc/wpa_supplicant.conf (if any)
# only add the network you need at boot time. **And keep the ctrl_interface** !!
ctrl_interface=/tmp/wpa_supplicant

network={
    ssid="MyNetwork"
    scan_ssid=1
    psk="network passphrase"
    key_mgmt=WPA-PSK
}

Three things to note:

1. You should delay the run of wpa_supplicant, or there's a chance you will get the error: Failed to connect to non-global ctrl_ifname error: No such file or directory . One second is enough, at least on my Raspberry Pi
2. Don't forget to copy the right WiFi firmware to the image. The manual_add_modules command doesn't copy the full firmware. For instance in my case I had to copy the following files:

/lib/firmware/brcm/brcmfmac43455-sdio.bin
/lib/firmware/brcm/brcmfmac43455-sdio.clm_blob
/lib/firmware/brcm/brcmfmac43455-sdio.txt

The manual_add_modules command copied only brcm/brcmfmac43455-sdio.bin which resulted in missing wlan0 interface.

3. Also copy the regulatory database (/lib/firmware/regulatory.db*).

@morfikov How exactly did you delay it? I tried adding sleep 60 right before calling /sbin/wpa_supplicant here, but am unsuccessful. If you could share your full configuration, that would be awesome. I am trying to set this up in a RaspPi 400

@seffs see here:

Ok, so I found your blog entry and followed all of the steps. It works!

There are two extra things to note:

1. I think it is better to first build the initramfs and figure out the exact files needed on boot for the wi-fi interface, then proceed with the rest of the steps (I also have a pi zero w and no mini HDMI converter, so for anyone in the same situation, this is strongly advised)

2. The resized root partition won't work in another raspberry pi or resized SD card unless you get to boot there from a second USB stick, chroot into the installation with LUKS and rebuild the initramfs. "Cross-initramfs-building" is NOT an option. I learned this the very hard way, that is, time.

2. The resized root partition won't work in another raspberry pi or resized SD card unless you get to boot there from a second USB stick, chroot into the installation with LUKS and rebuild the initramfs. "Cross-initramfs-building" is NOT an option. I learned this the very hard way, that is, time.

It worked well for me, I just had to use QEMU.

It worked well for me, I just had to use QEMU.

I tried to fit a 64gb installation into a 16 gb card (both rsync and resize/dd way). I made sure to use the same UUIDs for the partitions. SSH works on boot, but after entering the passphrase this follows:

Cannot initialize device-mapper. Is dm_mod kernel module loaded?

The same applied to the Pi400. Since I have another installation running on the Pi400, after chrooting and rebuilding it worked there, but rebuilding for the Pi Zero W failed.

Thanks for this scripts.
To add autodetection of wlan interface name in a_enable_wireless.sh
change

INTERFACE="wlp5s0"

to

INTERFACE=`ip link | awk '{if(substr($2,1,1) =="w") {gsub(":","",$2); print($2); exit;}}'`

it finds first interface by mask "w*",
and then add check if INTERFACE is zero string and skip wpa_supplicant.

if ! [ -z "$INTERFACE" ]; then

  # wpa supllicant stuff

fi

configure_networking

Hello, I'm having a little issue. I've tried the above (thanks for the scripts!) but I'm now stuck and not able to boot my server.

I think the connection is failing for some reason except that I never end up again in a command line to unlock my disk manually from the laptop (without using wifi).

Any idea how I can solve this?

Hello, I'm having a little issue. I've tried the above (thanks for the scripts!) but I'm now stuck and not able to boot my server.

You are welcome.

I am not using Debian on this scenarios anymore so I cannot be of much help but:

a) I think there have been some considerable changes to initramfs/dracut that could make all this not very usefull
b) The dropbear packages (dropbear-initramfs), if memory serves well, had some scripts on line with what is proposed here which may be useful.
c) The mandos-client package also had some sample scripts that could help you

Oh, and check the comments posted here by some users giving updates! like @morfikov & @leksmut (Thank you all for those comments!)