diff --git a/arch/arm/mach-stm32mp/cpu.c b/arch/arm/mach-stm32mp/cpu.c
index 592bfd413d..f6ed2ce0e4 100644
--- a/arch/arm/mach-stm32mp/cpu.c
+++ b/arch/arm/mach-stm32mp/cpu.c
@@ -483,6 +483,11 @@ static void setup_boot_mode(void)
 		STM32_UART7_BASE,
 		STM32_UART8_BASE
 	};
+	const u32 sdmmc_addr[] = {
+		STM32_SDMMC1_BASE,
+		STM32_SDMMC2_BASE,
+		STM32_SDMMC3_BASE
+	};
 	char cmd[60];
 	u32 boot_ctx = readl(TAMP_BOOT_CONTEXT);
 	u32 boot_mode =
@@ -525,7 +530,16 @@ static void setup_boot_mode(void)
 		break;
 	case BOOT_FLASH_SD:
 	case BOOT_FLASH_EMMC:
-		sprintf(cmd, "%d", instance);
+		if (instance > ARRAY_SIZE(sdmmc_addr))
+			break;
+		/* search associated sdmmc node in devicetree */
+		sprintf(cmd, "mmc@%x", sdmmc_addr[instance]);
+		if (uclass_get_device_by_name(UCLASS_MMC, cmd, &dev)) {
+			printf("mmc%d = %s not found in device tree!\n",
+			       instance, cmd);
+			break;
+		}
+		sprintf(cmd, "%d", dev_seq(dev));
 		env_set("boot_device", "mmc");
 		env_set("boot_instance", cmd);
 		break;
diff --git a/arch/arm/mach-stm32mp/include/mach/stm32.h b/arch/arm/mach-stm32mp/include/mach/stm32.h
index 5fdb893b0e..c11a9903f2 100644
--- a/arch/arm/mach-stm32mp/include/mach/stm32.h
+++ b/arch/arm/mach-stm32mp/include/mach/stm32.h
@@ -32,6 +32,10 @@
 #define STM32_UART7_BASE		0x40018000
 #define STM32_UART8_BASE		0x40019000
 
+#define STM32_SDMMC1_BASE		0x58005000
+#define STM32_SDMMC2_BASE		0x58007000
+#define STM32_SDMMC3_BASE		0x48004000
+
 #define STM32_SYSRAM_BASE		0x2FFC0000
 #define STM32_SYSRAM_SIZE		SZ_256K
 
diff --git a/board/st/stm32mp1/stm32mp1.c b/board/st/stm32mp1/stm32mp1.c
index 18b8870269..2faf5c81b4 100644
--- a/board/st/stm32mp1/stm32mp1.c
+++ b/board/st/stm32mp1/stm32mp1.c
@@ -841,6 +841,31 @@ const char *env_ext4_get_intf(void)
 	}
 }
 
+int mmc_get_boot(void)
+{
+	struct udevice *dev;
+	u32 boot_mode = get_bootmode();
+	unsigned int instance = (boot_mode & TAMP_BOOT_INSTANCE_MASK) - 1;
+	char cmd[20];
+	const u32 sdmmc_addr[] = {
+		STM32_SDMMC1_BASE,
+		STM32_SDMMC2_BASE,
+		STM32_SDMMC3_BASE
+	};
+
+	if (instance > ARRAY_SIZE(sdmmc_addr))
+		return 0;
+
+	/* search associated sdmmc node in devicetree */
+	snprintf(cmd, sizeof(cmd), "mmc@%x", sdmmc_addr[instance]);
+	if (uclass_get_device_by_name(UCLASS_MMC, cmd, &dev)) {
+		log_err("mmc%d = %s not found in device tree!\n", instance, cmd);
+		return 0;
+	}
+
+	return dev_seq(dev);
+};
+
 const char *env_ext4_get_dev_part(void)
 {
 	static char *const env_dev_part =
@@ -854,22 +879,16 @@ const char *env_ext4_get_dev_part(void)
 	if (strlen(env_dev_part) > 0)
 		return env_dev_part;
 
-	u32 bootmode = get_bootmode();
-
-	return dev_part[(bootmode & TAMP_BOOT_INSTANCE_MASK) - 1];
+	return dev_part[mmc_get_boot()];
 }
 
 int mmc_get_env_dev(void)
 {
-	u32 bootmode;
-
 	if (CONFIG_SYS_MMC_ENV_DEV >= 0)
 		return CONFIG_SYS_MMC_ENV_DEV;
 
-	bootmode = get_bootmode();
-
 	/* use boot instance to select the correct mmc device identifier */
-	return (bootmode & TAMP_BOOT_INSTANCE_MASK) - 1;
+	return mmc_get_boot();
 }
 
 #if defined(CONFIG_OF_BOARD_SETUP)