diff --git a/conf/machine/include/st-machine-common-stm32mp.inc b/conf/machine/include/st-machine-common-stm32mp.inc
index c7ddc47..d2c3c2f 100644
--- a/conf/machine/include/st-machine-common-stm32mp.inc
+++ b/conf/machine/include/st-machine-common-stm32mp.inc
@@ -308,7 +308,7 @@ ST_TOOLS_FOR_SDK_PERL = " \
 "
 
 # For some scripts in kernel source code
-ST_TOOLS_FOR_SDK_PERL = " \
+ST_TOOLS_FOR_SDK_PERL_append = " \
     nativesdk-perl-module-file-spec-functions \
 "