I've tried it: make SYSLINUX=/usr/src/nvidia-kernel-src.tar.gz also: make SYSLINUX=/usr/src/modules/nvidia-kernel-1.0.2880/debian/ both didn't work :( , also making a symlink from /usr/src/kernel-source-<version> to /usr/src/linux is not possible because I don't have a 'linux' directory there ...