1. Compile OpenWRT

1-1. Host Enviromnemt

OS: Ubuntu 22.4.1 LTS

1-2. Install utilities for compiling

Execute following command in terminal:

sudo apt update

sudo apt upgrade

sudo apt install build-essential clang flex g++ gawk gcc-multilib gettext git

libncurses5-dev libssl-dev python3-distutils rsync unzip zlib1g-dev pkg-config

1-3. Clone Source Code and Update

Clone the main branch and update it
git clone https://git.openwrt.org/openwrt/openwrt.git
cd openwrt
./scripts/feeds update -a
./scripts/feeds install -a

1-4. Menuconfig Setting

make menuconfig

Select the following setting:

Target System: MediaTek Ralink MIPS
Subtarget: MT7621 based boards
Target Profile: AP7621-001

Include the following features:

Kernel modules/Wireless drivers/kmod-mt7916-firmware
Kernel modules/Wireless drivers/kmod-mt76x2
Kernel modules/Wireless drivers/kmod-mt7915e
Kernel modules/Wireless Drivers/kmod-cfg80211
Kernel modules/Wireless Drivers/kmod-mac80211
(*optional for ap)Network/WirelessAPD/wpad
(*optional for ap)Network/WirelessAPD/hostapd-common
(*optional for iw tools)Base system/wireless-tools
(*optional for web server)LuCI/Collections/luci
(*optional for web server)LuCI/Collections/luci-ssl

1-5. (*optional) Turn on wireless ap in default

Revise the file /openwrt/package/kernel/mac80211/files/lib/wifi/mac80211.sh

set wireless.${name}.disabled=0

Save and compile.

1-6. Compile

make -j $(nproc) kernel_menuconfig

make -j $(nproc) defconfig download clean world V=s

2. Starting AP7621 platform for verify

After burning and booting your AP7621, you can check the interface on OpenWRT by the command:

ifconfig -a

and test the connection by ping.