Trying to get networkmanager running on a system built using buildroot. But when i try and bring upp the connection I get

    nmcli con up eth0
    "No suitable device found for this connection

and if i try and add eth0 to managed it accepts the command but still shows as unmanaged.
Using busybox as init system.

Options I added in buildroot for this:

    BR2_ROOTFS_DEVICE_CREATION_DYNAMIC_EUDEV=y
    BR2_PACKAGE_NETWORK_MANAGER=y
    BR2_PACKAGE_NETWORK_MANAGER_TUI=y
    BR2_PACKAGE_NETWORK_MANAGER_CLI=y

Can get networking running with ip command.

And /etc/networking/interface looks as the following:

    # Loopback interface lo
    auto lo
    iface lo inet loopback

nmcli version: 1.44.2
Is there something more i should look for? Maybe som options in the kernel I should check if they are set?

• Try and bring upp connection with:
  nmcli con up eth0
• Remove all but loopback from /etc/network/interfaces
• Try and add device to be managed

Expectation is that device should connect.