Yocto Setup TFTP/NFS¶

Running Yocto rootfs on Variscite board using TFTP & NFS¶

On the Host¶

Prepare the rootfs folder:

cd ~/var-fsl-yocto

sudo mkdir rootfs

cd rootfs

sudo tar --zstd -xvf ../build_x11/tmp/deploy/images/imx6ul-var-dart/fsl-image-gui-imx6ul-var-dart.rootfs.tar.zst

Make sure the NFS server is installed:

sudo apt install nfs-kernel-server

Edit /etc/exports, e.g.:

sudo nano /etc/exports

And add the following line to it (replace with the actual username):

/home/<uname>/var-yocto/rootfs    *(rw,sync,no_root_squash,no_all_squash,no_subtree_check)

Restart the NFS server:

sudo /etc/init.d/nfs-kernel-server restart

Make sure the TFTP server is installed:

Ubuntu 24.04 and newer:

sudo apt install xinetd tftpd-hpa tftp-hpa

Ubuntu 22.04 and older:

sudo apt install xinetd tftpd tftp

Configure tftpd-hpa for Ubuntu 24.04 and newer:

sudo nano /etc/default/tftpd-hpa

TFTP_USERNAME="tftp"
TFTP_DIRECTORY="/tftpboot"
TFTP_ADDRESS=":69"
TFTP_OPTIONS="--secure"

Configure tftpd for Ubuntu 22.04 and older:

ls /usr/sbin/in.tftpd

sudo nano /etc/xinetd.d/tftp

service tftp
{
    protocol = udp
    port = 69
    socket_type = dgram
    wait = yes
    user = nobody
    server = /usr/sbin/in.tftpd
    server_args = /tftpboot
    disable = no
}

And run:

sudo mkdir /tftpboot

sudo chmod -R 777 /tftpboot

sudo systemctl restart xinetd

sudo systemctl restart tftpd-hpa

cd ~/var-fsl-yocto/build_x11/

sudo cp tmp/deploy/images/imx6ul-var-dart/zImage.gz /tftpboot

find tmp/deploy/images/imx6ul-var-dart -maxdepth 1 -type f -name '*.dtb' -exec cp -v {} /tftpboot/ \;

Make adjustments to the rootfs:

When using NetworkManager on the target, configure NetworkManager not to manage the interface used for the NFS boot by adding the following to /home//var-yocto/rootfs/etc/NetworkManager/NetworkManager.conf:

[keyfile]
unmanaged-devices=interface-name:eth0

On the Target¶

Make sure you have a serial connection to the target.

Boot the board and hit any key to stop the autoboot and get to the U-Boot command line. Run the following in the U-Boot command line:

Replace <HOST_IP_ADDRESS> with the actual IP address of your host. Run ifconfig on the host to get it.

=> setenv serverip <HOST_IP_ADDRESS>

Replace <uname> with the actual username.

=> setenv nfsroot /home/<uname>/var-yocto/rootfs

=> setenv bootcmd run netboot

=> saveenv

You are all set. Connect the target board to the same network as the host using an Ethernet cable, power cycle it and it should boot over NFS.