iPXE and calling PHP

[NiKiZe]

you call this by using kernel? any particular reason?

You can use chain like you have tried, with autofree (not replace) that is a good way to do it, you just have to make sure that what is returned is actually a valid ipxe script.

make sure you have echo "#!ipxe\n";
and not echo "#!ipxe \n"; (note the space)
I would also recommend to skip ?>, that way anything trailing will be not be sent to the client.
And of course make sure what you fetch don't contain warnings or anything else. (also what is the error you are gettings?)

But with all that said what I would suggest is to use initrd instead to do the call, make sure to use --autofree