Prerequisites

Container Engine and Compose Spec tool of your choose:

• Podman (prefferable, Installation), Podman Compose (Installation)
  or
• Docker (Installation), Docker Compose V1 (Installation) or Docker Compose V2 (Installation)

Usage

git clone https://invent.kde.org/butirsky/plasma-mobile-sdk.git && cd openwrt-kroks
podman-compose run --no-deps --rm openwrt

This will run interactive script to build firmware. Press a key when asked.

The built firmware will be placed in bin/targets/ramips/mt76x8/

NB:

• If you prefer Docker, replace podman in the commands above with docker. For Docker Compose V2, use docker compose instead of docker-compose.

• Workaround for snapped Firefox's firmware image access problem:

  sudo chown bam bin/targets/ramips/mt76x8 bin/targets/ramips/mt76x8/openwrt-ramips-mt76x8-kroks_*-squashfs-sysupgrade.bin
  chmod g+w bin/targets/ramips/mt76x8 bin/targets/ramips/mt76x8/openwrt-ramips-mt76x8-kroks_*-squashfs-sysupgrade.bin 

• Find your router's IPv6 Link-Local Address:

  ip -6 neigh 
  # fe80::eef:afff:fecf:6fdf dev wlx060c0009f5ea lladdr 0c:ef:af:cf:6f:df router STALE
  
  # to parse:
  # lladdr=$(ip -6 neigh | cut -f 1,3 -d\  --output-delimiter=%)

  You can also use rdisc6 <interface> and ping ip6-allnodes

  It's recommended to save it in /etc/hosts under some name.

Flashing procedure:

• Get the router's full IPv6 Link-Local Address postfixed with % and the interface name and save it to a variable:

  lladdr=$(ping -c 1 modem | grep -oP '(?<=\().*(?=\):)') ; echo $lladdr
  # fe80::eef:afff:fecf:6fdf%wlx060c0009f5ea

  If it gives IPv4 address, that's OK, too.

  To check a name of the host currently in $lladdr:

  nslookup ${lladdr%\%*}
  # f.d.f.6.f.c.e.f.f.f.f.a.f.e.e.0.0.0.0.0.0.0.0.0.0.0.0.0.0.8.e.f.ip6.arpa	name = modem.

• Put image to the router:

  ssh root@$lladdr 'cat > /tmp/fw.bin' < ~/Downloads/openwrt-*kroks_*-squashfs-sysupgrade.bin

• (optional) Put configuration archive to the router:

  • If you have no LAN connection and there is no locally saved configuration yet, you might need to enable WiFi on the first boot before flashing firmware:
    https://openwrt.org/docs/guide-user/installation/flashing_openwrt_with_wifi_enabled_on_first_boot

    tar -C files/ -czv etc/uci-defaults/97-enable_wifi | ssh root@$lladdr 'cat > /tmp/cf.tgz'

  • Alternatively, if you have locally saved configuration but the router is not configured yet:

    ssh root@$lladdr 'cat > /tmp/cf.tgz' < ~/Downloads/backup-OpenWrt-*

• Flashing the image:

  • If you passed configuration above, flash it along with the image:

    ssh root@$lladdr sysupgrade -n -f /tmp/cf.tgz /tmp/fw.bin

  • In other cases, just pass firmware image to the command, it will restore current configuration unless -n option is present:

    ssh root@$lladdr sysupgrade /tmp/fw.bin

  You might need forcing option first time:

  	-F | --force
  	             Flash image even if image checks fail, this is dangerous!
  	--ignore-minor-compat-version
  		     Flash image even if the minor compat version is incompatible.
  

Restoring procedure:

• (optional) Hard factory reset:
  https://openwrt.org/docs/guide-user/troubleshooting/failsafe_and_factory_reset#jffs2_reset

  ssh -t root@$lladdr 'umount /overlay && jffs2reset -y && reboot'

• (optional) Configuration restore:

  ssh -o StrictHostKeyChecking=no root@$lladdr 'sysupgrade -r - && (ifup lan &)' < ~/Downloads/backup-OpenWrt* &&
  sleep 1 &&
  ssh root@$lladdr ifconfig

  Now you can access LuCI in browser using stable fd00::/8 Global address again.

• (optional) If you have no SIM card in local SIM1 reader slot, there is not enough packages installed yet to switch the SIM so you might need to do it manually:

  • ssh root@$lladdr << "EOF"
    tail /sys/class/gpio/modem1*/value
    set -x
    
    echo 0 | tee /sys/class/gpio/modem1power/value
    sleep 1
    
    echo 0 | tee /sys/class/gpio/modem1*sim*/value
    
    set +x
    tail /sys/class/gpio/modem1*/value
    set -x
    
    echo 1 | tee /sys/class/gpio/modem1$(cat /etc/sim)/value
    sleep 1
    
    echo 1 | tee /sys/class/gpio/modem1power/value
    
    ifup wan
    
    set +x
    tail /sys/class/gpio/modem1*/value
    EOF

  • Alternatively, you might want to set up a temporal managed connection to your existing WiFi hotspot (e.g. on mobile) to download missing packages:
    https://openwrt.org/docs/guide-user/network/wifi/connect_client_wifi#command-line_instructions

    ssh root@$lladdr 'sh && service system reload && (ifup lan &)' < files/etc/uci-defaults/98-client_wifi-dhcp_client &&
    sleep 1 &&
    ssh root@$lladdr ifconfig

    You can also access the router by hostname now.
  • Alternatively, hybrid WiFi AP+STA mode can be used:
    https://openwrt.org/docs/guide-user/network/wifi/ap_sta

    ssh root@$lladdr 'sh; ifup wan' < files/etc/uci-defaults/99-ap_sta

• Packages to install:

  ssh root@$lladdr << "EOF"
  grep -q IceG_repo /etc/opkg/customfeeds.conf || echo 'src/gz IceG_repo https://github.com/4IceG/Modem-extras/raw/main/myrepo' >> /etc/opkg/customfeeds.conf
  wget https://github.com/4IceG/Modem-extras/raw/main/myrepo/IceG-repo.pub -O /tmp/IceG-repo.pub
  opkg-key add /tmp/IceG-repo.pub
  wget http://openwrt.132lan.ru/packages/21.02/packages/add.sh -O - | sh
  
  opkg update
  
  opkg install \
  kmod-usb-serial-option \
  chat \
  luci-proto-qmi \
  luci-app-atinout \
  luci-app-modeminfo \
  modeminfo-serial-quectel \
  modeminfo-qmi \
  qmi-utils \
  hostapd-utils \
  luci-app-commands \
  bash \
  luci-app-sms-tool-js \
  luci-app-attendedsysupgrade \
  # luci-app-smstools3
  EOF

Credits

Many thanks to:

• Kroks for publishing OpenWrt sources for their routers and being responsive on Helpdesk
• MrFuture for creating a topic on 4PDA and publishing SIM switching method via GPIO
• GlshchnkLx and linaro for GPIO fix and overall support
• other members of the Kroks topic on 4PDA