pxelinux chain to iPXE no more network devices

[mimiko]

Hello.
I try to boot windows setups using wimboot. For a long time I use pxelinux, so I use iPXE to load wimboot and other files like this:

label Microsoft Windows 7 Setup
menu label Microsoft Windows 7 Setup
kernel ipxe.krn
APPEND dhcp && kernel http://server.com/wds/x86/wimboot && initrd http://server.com/wds/x86/bcd BCD && initrd http://server.com/wds/x86/boot.sdi boot.sdi && initrd http://server.com/wds/x86/boot-win7_2k8_x86.wim boot.wim && boot

This works in VirtualBox environment. Worked at modern cimputer. But does not work on an 5y old computer. After pxelinux loads and starts ipxe.krn, there is nothing happens and it try to find other booting defices.

I've remode append command. After loading ipxe.krn I press Ctrl+B to see some info. And I get: no more network devices.

How to resolve this problem?

Another question. pxelinux have an option to skip loading menus and other if Scroll Lock is not activated, or Ctrl is not pressed. Is such a option for iPXE?