diff --git a/.gitignore b/.gitignore
index 232a065..8fe9fcf 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1 +1,6 @@
 /sdcard.img
+/root_overlay/etc/door_tokens
+/root_overlay/etc/dropbear
+/root_overlay/root/key
+/root_overlay/bin/test.py
+/root_overlay/bin/poll_desfire
diff --git a/Makefile b/Makefile
index b6204f8..69238af 100644
--- a/Makefile
+++ b/Makefile
@@ -1,23 +1,46 @@
+BR2_EXTERNAL=../br_external
+
 all: sdcard.img
 
-sdcard.img: buildroot/.config root_overlay/root/.ssh/authorized_keys
+sdcard.img: root_overlay buildroot/.config root_overlay/root/.ssh/authorized_keys
 	make -C buildroot all
 	cp buildroot/output/images/sdcard.img sdcard.img
 
+root_overlay: root_overlay/bin/test.py
+root_overlay: root_overlay/etc/door_tokens
+root_overlay: root_overlay/etc/dropbear/dropbear_ecdsa_host_key
+root_overlay: root_overlay/root/.ssh/authorized_keys
+root_overlay: root_overlay/root/key
+
 root_overlay/root/.ssh/authorized_keys: ~/.ssh/id_rsa.pub
-	cp ~/.ssh/id_rsa.pub root_overlay/root/.ssh/authorized_keys
+	cp ^< $@
 
 buildroot/.config: config
 	ln -sf ../config buildroot/.config
 
+root_overlay/etc/door_tokens:
+	mkdir -p `dirname $@`
+	touch $@
+
+root_overlay/root/key:
+	mkdir -p `dirname $@`
+	dd if=/dev/urandom of=$@ bs=1 count=16
+
+root_overlay/bin/test.py: door_control/door.py
+	mkdir -p `dirname $@`
+	cp $< $@
+
+root_overlay/etc/dropbear/dropbear_ecdsa_host_key:
+	mkdir -p `dirname $@`
+	ssh-keygen -t ecdsa -f $@
+
 clean:
 	make -C buildroot clean
 	rm -f sdcard.img
 	rm -f root_overlay/root/.ssh/authorized_keys
-	rm -f root_overlay/bin/poll_desfire
 	rm -f root_overlay/bin/test.py
 
 menuconfig:
 	make -C buildroot menuconfig
 
-.PHONY: all clean sdcard.img menuconfig
+.PHONY: all clean sdcard.img menuconfig root_overlay