There is a mistake in wrlinux-1.x/wrlinux/templates/features/rt/README file.
It should be --with-template=feature/rt not --enable-template=feature/rt. IDENTIFIER = WIND00114736
WIND00114738.zip is for 1.4
WIND00114743.zip is for 1.5
1. Unzip the patch under [install_dir]/updates
2. Install the patch CD by entering the patch CD directory and run setup_linux.
3. This is a source only patch so you will have to build the kernel
4. Issue a make fs and make the kernel in a configured directory.
5. Upload the kernel and rootfs into the target and boot it up.