Setting up VLAN before fetching ignition config

[0xalex88]

I was looking at this docs page to be able to set vlan tagging and static IP before trying to get the ignition config.
I'm using matchbox to return this IPXE script (ipxe vlan works fine by using vcreate --tag 1 net1):

#!ipxe
kernel /assets/flatcar/3815.2.2/flatcar_production_pxe.vmlinuz initrd=flatcar_production_pxe_image.cpio.gz flatcar.config.url=http://10.1.0.1:8080/ignition?uuid=${uuid}&mac=${mac:hexhyp} flatcar.first_boot=yes ip=10.1.2.1 netmask=255.255.0.0 ksdevice=vlan.1 vlan=vlan.1:enp4s0f1
initrd /assets/flatcar/3815.2.2/flatcar_production_pxe_image.cpio.gz
boot

however when booting the kernel rejects the arguments with:

Unknown kernel command line parameters "ip=10.1.2.1 netmask=255.255.0.0 ksdevice=vlan.1 vlan=vlan.1:enp4s0f1", will be passed to user space

Any idea on how to get the private instance set up?

Update:

I've also tried with vlan=enp4s0f1.1:enp4s0f1 ip=10.1.2.1:::255.255.0.0::enp4s0f1.1::::: and I'm getting

99-parse-ip-for-networkd.sh[497]: Warning: Empty autoconf values default to dhcp
dracut: FATAL: For argument 'ip=10.1.2.1:::255.255.0.0::enp4s0f1.1:::::'\nSorry, setting client-ip does not  make sense for dhcp

Update 2:

Fixed the error above by adding none but still no vlan, maybe dracut used by flatcar doesn't support adding the vlan config?

[jepio]

This is the script responsible for setting up networking from the initrd:
https://github.com/flatcar/bootengine/blob/8da532c809c89a9c434ada0fa9532a1c1bf49f4c/dracut/03flatcar-network/parse-ip-for-networkd.sh

reading it, it doesn't seem to support setting up vlan

[0xalex88]

Thanks, I guess there's no way then