diff --git a/tools/make-functions b/tools/make-functions
index e581ceffb..39d941169 100644
--- a/tools/make-functions
+++ b/tools/make-functions
@@ -514,6 +514,7 @@ enterchroot() {
 		BUILDTARGET="${BUILDTARGET}" \
 		CROSSTARGET="${CROSSTARGET}" \
 		BUILD_ARCH="${BUILD_ARCH}" \
+		BUILD_PLATFORM="${BUILD_PLATFORM}" \
 		CCACHE_DIR=/usr/src/ccache \
 		CCACHE_COMPRESS="${CCACHE_COMPRESS}" \
 		CCACHE_COMPILERCHECK="${CCACHE_COMPILERCHECK}" \