Building the firmware

As mentioned before, we will download the latest version of OpenWrt and build it for x86. On a modern Ubuntu/Debian distribution, you just need to follow these steps:

1. Prepare the build environment:

   sudo apt update

   sudo apt install build-essential clang flex g++ gawk gcc-multilib gettext git libncurses5-dev libssl-dev python3-distutils rsync unzip zlib1g-dev

2. Check out the most recent version of the firmware:

   git clone  --depth 1 --branch v21.02.3 https://git.openwrt.org/openwrt/openwrt.git

   cd openwrt

3. Update the feeds:

   /scripts/feeds update -a

   /scripts/feeds install -a

4. Configure the firmware image and the kernel:

   make menuconfig #here you can select cross compilation to other hardware if you'd like

   make -j $(nproc) kernel_menuconfig

   # Build the firmware image

   make -j $(nproc) defconfig download clean world #the -j parallelize compilation for your CPU

The make menuconfig command will allow us to select the target hardware that we prefer...