diff --git a/plat/st/stm32mp1/stm32mp1_private.c b/plat/st/stm32mp1/stm32mp1_private.c
index 5944602..eb8bc27 100644
--- a/plat/st/stm32mp1/stm32mp1_private.c
+++ b/plat/st/stm32mp1/stm32mp1_private.c
@@ -575,3 +575,22 @@
 
 	stm32mp_clk_disable(RTCAPB);
 }
+
+void stm32_get_boot_interface(uint32_t *interface, uint32_t *instance)
+{
+	static uint32_t itf;
+
+	if (itf == 0U) {
+		uint32_t bkpr = tamp_bkpr(TAMP_BOOT_MODE_BACKUP_REG_ID);
+
+		stm32mp_clk_enable(RTCAPB);
+
+		itf = (mmio_read_32(bkpr) & TAMP_BOOT_MODE_ITF_MASK) >>
+			TAMP_BOOT_MODE_ITF_SHIFT;
+
+		stm32mp_clk_disable(RTCAPB);
+	}
+
+	*interface = itf >> 4;
+	*instance = itf & 0xFU;
+}