diff --git a/meta/recipes-devtools/elfutils/elfutils_0.187.bb b/meta/recipes-devtools/elfutils/elfutils_0.187.bb
index 31983dfd6b..d03da61353 100644
--- a/meta/recipes-devtools/elfutils/elfutils_0.187.bb
+++ b/meta/recipes-devtools/elfutils/elfutils_0.187.bb
@@ -56,6 +56,7 @@ do_compile_ptest() {
 	cd ${B}/tests
 	oe_runmake buildtest-TESTS oecheck
 }
+PTEST_PARALLEL_MAKE = ""
 
 do_install_ptest() {
 	if [ ${PTEST_ENABLED} = "1" ]; then
diff --git a/meta/recipes-devtools/flex/flex_2.6.4.bb b/meta/recipes-devtools/flex/flex_2.6.4.bb
index c7cd965347..8736b3585e 100644
--- a/meta/recipes-devtools/flex/flex_2.6.4.bb
+++ b/meta/recipes-devtools/flex/flex_2.6.4.bb
@@ -60,6 +60,7 @@ RDEPENDS:${PN}-ptest += "bash gawk make"
 do_compile_ptest() {
 	oe_runmake -C ${B}/tests -f ${B}/tests/Makefile top_builddir=${B} INCLUDES=-I${S}/src buildtests
 }
+PTEST_PARALLEL_MAKE = ""
 
 do_install_ptest() {
 	mkdir -p ${D}${PTEST_PATH}/build-aux/