New line removed from core config file after snap set

snapd
1

Running the test main/snapctl-configure-core on pi 2 and 3 there is a failure running this piece of code:

echo "Check that pi config handline works"
if [ -e /boot/uboot/config.txt ]; then
    cp /boot/uboot/config.txt config.txt.save

    snap set core pi-config.hdmi-mode=1
    cat /boot/uboot/config.txt | MATCH ^hdmi_mode=1
    snap set core pi-config.hdmi-mode=""
    cat /boot/uboot/config.txt | MATCH ^#hdmi_mode=1

    echo "Ensure the config.txt are fully undo when an option is unset"
    if ! diff -u /boot/uboot/config.txt config.txt.save; then
        echo "error: unexpected diff in /boot/uboot/config.txt"
        exit 1
    fi
fi

Basically, what it is happening, is that the file /boot/uboot/config.txt does not contains a new line at the end of the file as it had initially, and it makes the diff to fail.

The error obtained https://paste.ubuntu.com/25728285/

It works properly on vms running ubuntu core, but it fails on boards.