kernel Linux 3.x (probably Linux-libre) C library EGLIBC or uClibc (maybe uClibc could be a future option) standard user utilities BusyBox SSH server and client Dropbear package manager opkg boot loader LILO, RedBoot, or DAS U-Boot compiler toolchain GCC GNU Binutils make GNU Make build systems GNU Automake GNU Autoconf CMake (if any packages use it)