Hardset flatcar initrd to fix booting

Flatcar appears to have issues with initrd.magic,
so hardsetting to initrd

Fixes: https://github.com/netbootxyz/netboot.xyz/issues/1070

CHANGELOG.md

@@ -5,6 +5,8 @@ All notable changes to this project will be documented in this file.
 ## [Unreleased]
 
 ## [2.0.55]
+#### Fixed
+- Hardset Flatcar Linux initrd to fix booting (https://github.com/netbootxyz/netboot.xyz/issues/1070)
 
 ## [2.0.54]
 #### Added

roles/netbootxyz/templates/menu/flatcar.ipxe.j2

@@ -28,7 +28,7 @@ goto flatcar_exit
 :edge
 set release ${menu}
 set base-url http://${release}.release.flatcar-linux.net/amd64-usr/current
-kernel ${base-url}/flatcar_production_pxe.vmlinuz ${flatcar_firstboot} ${flatcar_params} flatcar.autologin=tty1 flatcar.autologin=ttyS0 {{ kernel_params }}
+kernel ${base-url}/flatcar_production_pxe.vmlinuz ${flatcar_firstboot} ${flatcar_params} flatcar.autologin=tty1 flatcar.autologin=ttyS0 initrd=flatcar_production_pxe_image.cpio.gz ${cmdline}
 initrd ${base-url}/flatcar_production_pxe_image.cpio.gz
 boot
 goto flatcar_exit