diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..4c1b90c
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+overlay/etc/release
diff --git a/build.sh b/build.sh
index 77f84c3..8786440 100755
--- a/build.sh
+++ b/build.sh
@@ -1,4 +1,7 @@
 #!/bin/sh
+PANDA_REV=`git rev-parse HEAD`
+BR_REV=`(cd buildroot && git rev-parse HEAD)`
+echo "panda_linux $PANDA_REV (buildroot $BR_REV)" > overlay/etc/release
 (
 	cd buildroot
 	BR2_DEFCONFIG=../buildroot.config make defconfig &&