diff --git a/builder/chroot-script.sh b/builder/chroot-script.sh
index ad9a4df..d065184 100644
--- a/builder/chroot-script.sh
+++ b/builder/chroot-script.sh
@@ -112,6 +112,7 @@ echo 'deb http://archive.raspberrypi.org/debian/ jessie main' | tee /etc/apt/sou
 
 # reload package sources
 apt-get update
+apt-get upgrade -y
 
 # install WiFi firmware packages (same as in Raspbian)
 apt-get install -y \