diff --git a/plat/st/common/include/stm32mp_common.h b/plat/st/common/include/stm32mp_common.h
index 9ca5d16..7508004 100644
--- a/plat/st/common/include/stm32mp_common.h
+++ b/plat/st/common/include/stm32mp_common.h
@@ -113,4 +113,8 @@
 void stm32_save_boot_interface(uint32_t interface, uint32_t instance);
 void stm32_get_boot_interface(uint32_t *interface, uint32_t *instance);
 
+#if !STM32MP_USE_STM32IMAGE && PSA_FWU_SUPPORT
+void stm32mp1_fwu_set_boot_idx(void);
+#endif /* !STM32MP_USE_STM32IMAGE && PSA_FWU_SUPPORT */
+
 #endif /* STM32MP_COMMON_H */