VAR-SOM-MX6 - Yocto Setup TFTP/NFS

Running Yocto rootfs on Variscite board using TFTP & NFS

On the Host

Prepare the rootfs folder:

$ cd ~/var-fslc-yocto
$ sudo mkdir rootfs
$ cd rootfs
$ sudo tar xvf ../build_xwayland//images/var-som-mx6/fsl-image-gui-var-som-mx6.tar.gz

Make sure the NFS server is installed:

$ sudo apt-get install nfs-kernel-server

Edit /etc/exports. E.g.

$ sudo nano /etc/exports

...and add the following line to it (replace <uname> with the actual username):

/home/<uname>/var-fslc-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-get install xinetd tftpd-hpa tftp-hpa

# Ubuntu 22.04 and older
$ sudo apt-get 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-fslc-yocto/build_xwayland/
$ sudo cp /images/var-som-mx6/uImage /tftpboot
$ for f in /images/var-som-mx6/*.dtb; do if [[ -L $f ]] && [[ $f != *var-som-mx6.dtb ]]; then sudo cp $f /tftpboot; fi done
$ sudo rename 's/uImage-//' /tftpboot/uImage-*.dtb

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/<uname>/var-fslc-yocto/rootfs/etc/NetworkManager/NetworkManager.conf:

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

Enable DNS:

$ sudo ln -fs /proc/net/pnp /home/<uname>/var-fslc-yocto/rootfs/etc/resolv.conf

On the Target

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.