OpenWrt ImageBuilder: Custom Firmware in a Few Commands

The most common question when starting with OpenWrt is: "I don't want to build the entire source tree just to add a couple of packages." The official ImageBuilder exists exactly for that: it only repackages, it does not recompile the kernel.

Assumptions: host Ubuntu 22.04 / Debian 12, target x86_64, OpenWrt 23.05.5.

1. Download the ImageBuilder for your target

cd ~/openwrt
wget https://downloads.openwrt.org/releases/23.05.5/targets/x86/64/openwrt-imagebuilder-23.05.5-x86-64.Linux-x86_64.tar.xz
tar xf openwrt-imagebuilder-*.tar.xz
cd openwrt-imagebuilder-23.05.5-x86-64.Linux-x86_64

2. Inspect the available packages

The ImageBuilder ships a packages index, so you can simply grep:

make info | grep -i luci
# common: luci luci-ssl-openssl luci-app-* etc.

Note: the ImageBuilder only includes packages that are in sync with the official feeds. To add a self-compiled .ipk, drop it into the packages/ directory before running make.

3. Build a firmware with extra packages

make image \
  PROFILE=generic \
  PACKAGES="luci luci-ssl-openssl kmod-usb-storage block-mount e2fsprogs"

The resulting image lives under bin/targets/x86/64/:

openwrt-23.05.5-x86-64-generic-squashfs-combined-efi.img.gz

Before flashing, remember:

gzip -dk openwrt-*.img.gz
# For x86 you can validate with qemu or a disk writer (dd / balenaEtcher)

4. Getting your own package onto the image

Self-compiled .ipk files can be installed with opkg, no repackaging needed:

scp mypackage_1.0_1_x86_64.ipk root@192.168.1.1:/tmp/
ssh root@192.168.1.1 "opkg install /tmp/mypackage_1.0_1_x86_64.ipk"

Wrap-up

Scenario	Recommended tool
Only official packages, fast repack	ImageBuilder
Deep kernel/driver customization	Source build (SDK)
Everyday package management	opkg online install

Next up: trimming the kernel with menuconfig when building from source.