diff --git a/kernel/Dockerfile b/kernel/Dockerfile
index 4fbbf944f..8d2d43cf0 100644
--- a/kernel/Dockerfile
+++ b/kernel/Dockerfile
@@ -112,7 +112,7 @@ RUN case $(uname -m) in \
     fi && \
     make defconfig && \
     make oldconfig && \
-    if [ -z "${EXTRA}" ] && [ -z "${DEBUG}" ]; then diff .config ${KERNEL_DEF_CONF}; fi
+    if [ -z "${EXTRA}" ] && [ -z "${DEBUG}" ]; then diff -u .config ${KERNEL_DEF_CONF}; fi
 
 
 # Kernel