Downloading syslinux files on build

Dockerfile

@@ -3,17 +3,27 @@ FROM debian:buster
 RUN apt update
 RUN apt install -y make debootstrap supervisor isc-dhcp-server tftpd-hpa busybox squashfs-tools
 
-# Builds Linux for cloning image. The Makefile in linux/ would download base
+# Downloads base Debian 10 to /linux/build/cache. The Makefile in linux/ would
-# debian system to linux/build/cache itself, but to speed up rebuilding this
+# download base debian system to linux/build/cache itself, but to speed up
-# Docker container the download is run separately to avoid repeating it in
+# rebuilding this Docker container the download is run separately to avoid
-# future builds.
+# repeating it in future builds.
 ADD linux /linux
 RUN mkdir -p linux/build && debootstrap buster linux/build/cache
+
+# Copies src/tftpboot directory to /tftpboot
+ADD src/tftpboot /tftpboot
+
+# Downloads Syslinux and moves ldlinux.c32 and pxelinux.0 files to /tftpboot
+RUN wget https://mirrors.edge.kernel.org/pub/linux/utils/boot/syslinux/syslinux-6.03.tar.gz && \
+	tar -xzvf syslinux-6.03.tar.gz && \
+	cp syslinux-6.03/bios/core/pxelinux.0 /tftpboot/pxelinux.0 && \
+	cp syslinux-6.03/bios/com32/elflink/ldlinux/ldlinux.c32 /tftpboot/ldlinux.c32
+
+# Builds Linux with its Makefile
 RUN cd /linux && make
 
 # Creates and populates /tftpboot directory. Files stored there will be served
 # by TFTP and HTTP (on port 8014).
-ADD src/tftpboot /tftpboot
 RUN cp /linux/build/rootfs/initrd.img /tftpboot/initrd.img && \
 	cp /linux/build/rootfs/vmlinuz /tftpboot/vmlinuz && \
 	mksquashfs /linux/build/rootfs /tftpboot/root.squashfs