No Boot PXE with Lenovo L440

Hi everyone,

We have a new Thinkpad Lenovo L440 and we can't boot PXE. Our Imaging server is 11.2.4, installed on a Windows Server 2008 SP1

We changed the BIOS for booting in Legacy Mode but no change. Laptop can't receive any IP address.... We have upgraded the BIOS to the most recent version but still no luck...

any idea ?

booting from a CD with Imaging is working.