iPXE Can't Find NIC

[teepee]

I am not having any luck getting iPXE to work. I have a HP tc4200 laptop. It has a Broadcom BCM5751M NIC (according to lspci). I downloaded the source for iPXE and built it. I put the ipxe.usb file on a USB drive using "win32diskimager". I boot from the USB drive, and press CTRL-B to get to the prompt. I type in ifstat and get nothing but the prompt.

What can I do?

[daniel]

I have built ipxe.efi 64 bit,my network device card is pcnet32,but ipxe.efi can't attach network card,i only get the log "No more network devices".but if boot to ipxe via ipxe.iso,ipxe can detected the network device card.the prompt is "No more devices".
I think that you have fixed the bug about ipxe.efi can't detect UNDI driver,

BTW,
After debug ipxe.efi,i found that only call efi_pci.c\efipci_driver_startup but not call efi_pci.c\efipci_start,so i think pci device not been attach.
Do you know the root cause？
Although I have read a topic about "Using iPXE with UNDI driver",but i can't find the root cause.