tftp booting from a windows TFTP server gives issues.

PXE sends a leading / that needs to be removed.

e.g. chain tftp://ip.of.server/boot\x64\wdsbnp.com

PXE send TFTP Request /Boot\x64\wdsnbp.com
That first "/" must be removed.

Original fix from
http://forum.ipxe.org/archive/index.php/thread-7242.html