export CROSS_COMPILE=aarch64-linux-gnu-
export ARCH=arm64

make defconfig
make Image -j8
make rockchip/rk3399-evb.dtb
make modules M=./drivers/net/wireless/broadcom/brcm80211/
make modules M=./drivers/input/touchscreen

sudo apt-get install qemu-user-static debootstrap

sudo debootstrap \
        --arch=arm64 \
        --verbose \
        --foreign \
        --include=vim,iproute2,wpasupplicant \
        focal \
        rootfs

sudo cp /usr/bin/qemu-aarch64-static rootfs/usr/bin/
 
//wsl or docker要执行下面的语句   
update-binfmts --display qemu-aarch64   //Check if aarch64 qemu binary is enabled on your system
sudo update-binfmts --import qemu-aarch64  //if it's disabled or not registered at all, use this command to fix it:
 
sudo chroot rootfs/ /bin/bash

/debootstrap/debootstrap --second-stage
passwd root

// 配置启动菜单, PARTUUID可以在uboot中查看(以root用户运行以下命令)
mkdir -p rootfs/boot/extlinux
cat << EOF > rootfs/boot/extlinux/extlinux.conf
menu title select your system
timeout 10
default Ubuntu 20.04

label Ubuntu 20.04
  kernel /boot/Image
  fdt /boot/rk3399-evb.dtb
  append earlyprintk console=ttyFIQ0,115200n8 rw noinitrd init=/sbin/init rootfstype=ext4 rootwait root=PARTUUID=f371dcf2-c2df-47e0-8ddf-ad708756d7a1 console=ttyS2,115200n8
  
label Ubuntu recovery
  kernel /boot/recovery/Image
  fdt /boot/recovery/rk3399-evb.dtb
  append earlyprintk console=ttyFIQ0,115200n8 rw noinitrd init=/sbin/init rootfstype=ext4 rootwait root=PARTUUID=f371dcf2-c2df-47e0-8ddf-ad708756d7a1 console=ttyS2,115200n8  
EOF

// 复制内核与设备树
sudo cp kernel/arch/arm64/boot/Image rootfs/boot
sudo cp kernel/arch/arm64/boot/dts/rockchip/rk3399-evb.dtb rootfs/boot

// 复制WIFI驱动文件与固件
sudo mkdir -p rootfs/lib/modules/5.4.143+
sudo cp kernel/drivers/net/wireless/broadcom/brcm80211/brcmfmac/brcmfmac.ko rootfs/lib/modules/5.4.143+/
sudo cp kernel/drivers/net/wireless/broadcom/brcm80211/brcmsmac/brcmsmac.ko rootfs/lib/modules/5.4.143+/
sudo cp kernel/drivers/net/wireless/broadcom/brcm80211/brcmutil/brcmutil.ko rootfs/lib/modules/5.4.143+/

git clone https://gitee.com/qzhang1535/brcmfmac_sdio-firmware.git
sudo mkdir -p rootfs/lib/firmware
sudo cp -a brcmfmac_sdio-firmware rootfs/lib/firmware/brcm