Any network commands don’t work.

[NiKiZe]

First of, if ifstat does not show any devices, that indicates that there is no nics detected by iPXE at all.
are you sure you don't get any messages when running dhcp?

Are you sure your script actually freezes? my guess is that it instead exits due to some kind of error.

What build of iPXE are you running? (as in what is the filename of the file that you are using if you built it from the iPXE sources)
That information tells us which platform it is running under, as well as which drivers are included in the build.

When we have this we can start to identify why no NIC is detected, and for this it is also a good idea to provide the PCI ID of the device.
Best way to collect this is to run lspci -nn under linux, and copy the relevant line that contains your Ethernet device.