diff --git a/.buildbot/openwrt/build.sh b/.buildbot/openwrt/build.sh
index 0ecd5cd..5ebd28f 100755
--- a/.buildbot/openwrt/build.sh
+++ b/.buildbot/openwrt/build.sh
@@ -46,6 +46,8 @@ make info
 
 # Double the size of the root partition
 echo "CONFIG_TARGET_ROOTFS_PARTSIZE=208" >> .config
+# Disable ext4 images
+echo "CONFIG_TARGET_ROOTFS_EXT4FS=n" >> .config
 
 # Setup files
 mkdir -p files/root/.ssh