diff --git a/config/functions b/config/functions
index 1b6e2ef307..29937ff181 100644
--- a/config/functions
+++ b/config/functions
@@ -2,6 +2,8 @@ setup_toolchain() {
   if [ "$1" = target ]; then
     export DESTIMAGE="target"
 
+    unset CPP
+
     export CC=$TARGET_CC
     export CXX=$TARGET_CXX
     export LD=$TARGET_LD
@@ -26,6 +28,8 @@ setup_toolchain() {
   elif [ "$1" = host ]; then
     export DESTIMAGE="host"
 
+    unset CPP
+
     export AWK=$HOST_AWK
     export CC=$HOST_CC
     export CXX=$HOST_CXX
diff --git a/config/path b/config/path
index aa00a5ec44..6867e03db8 100644
--- a/config/path
+++ b/config/path
@@ -108,6 +108,8 @@ SSL_CERTIFICATES="/etc/pki/tls"
 TOOLCHAIN_LANGUAGES=c
 [ "$TOOLCHAIN_CXX" = yes ] && TOOLCHAIN_LANGUAGES=${TOOLCHAIN_LANGUAGES},c++
 
+unset TARGET_CPP
+
 TARGET_CC=${TARGET_PREFIX}gcc
 TARGET_CXX=${TARGET_PREFIX}g++
 TARGET_LD=${TARGET_PREFIX}ld
@@ -125,6 +127,8 @@ TARGET_PKG_CONFIG_PATH=""
 TARGET_PKG_CONFIG_LIBDIR="$SYSROOT_PREFIX/usr/lib/pkgconfig:$SYSROOT_PREFIX/usr/share/pkgconfig"
 TARGET_PKG_CONFIG_SYSROOT_DIR="$SYSROOT_PREFIX"
 
+unset HOST_CPP
+
 HOST_AWK=gawk
 HOST_CC=$ROOT/$TOOLCHAIN/bin/host-gcc
 HOST_CXX=$ROOT/$TOOLCHAIN/bin/host-g++