How do I build in the EFI environment?

first run "build.cmd" in this directory

This sets up the build environment, then:

cd sdk\build\nt32 for the 32 bit environment under the emulator or,
cd sdk\build\sal64 for the 64 bit Itanium environment (Make sure you started razzle
as "...\razzle.cmd Win64")

nmake

cd ..\..\..

then, go to your project dir. (Or pickup hello and modify it) and type bz / bcz

This will produce your binary