diff --git a/configs/P5040DS_SECURE_BOOT_defconfig b/configs/P5040DS_SECURE_BOOT_defconfig
index 73b728b..5d7e1d0 100644
--- a/configs/P5040DS_SECURE_BOOT_defconfig
+++ b/configs/P5040DS_SECURE_BOOT_defconfig
@@ -32,4 +32,5 @@
 CONFIG_USB_STORAGE=y
 CONFIG_RSA=y
 CONFIG_SPL_RSA=y
+CONFIG_RSA_SOFTWARE_EXP=y
 CONFIG_OF_LIBFDT=y