--- a/board/mediatek/mt7622/mt7622_rfb.c
+++ b/board/mediatek/mt7622/mt7622_rfb.c
@@ -10,7 +10,9 @@
 #include <env.h>
 #include <init.h>
 #include <asm/global_data.h>
+#include <asm/io.h>
 #include <linux/delay.h>
+#include <linux/libfdt.h>
 
 #ifndef CONFIG_RESET_BUTTON_LABEL
 #define CONFIG_RESET_BUTTON_LABEL "reset"
@@ -21,8 +23,46 @@
 #include <nmbm/nmbm.h>
 #include <nmbm/nmbm-mtd.h>
 
+#define MT7622_TOPRGUSTRAP_PAR			0x10212060
+#define MT7622_BOOT_SEQ_MASK			0x18
+#define MT7622_BOOT_SEQ_SHIFT			3
+#define MT7622_BOOT_SEQ_NOR_EMMC_SDXC		0x0
+#define MT7622_BOOT_SEQ_SPI_NAND_EMMC_SDXC	0x1
+#define MT7622_BOOT_SEQ_NAND_EMMC_SDXC		0x2
+#define MT7622_BOOT_SEQ_SDXC_EMMC_NAND		0x3
+
+#define MT7622_GPIO_MODE0			0x10211300
+#define MT7622_GPIO_NAND_MODE_MASK		0x00f00000
+#define MT7622_GPIO_NAND_MODE_SHIFT		20
+#define MT7622_GPIO_NAND_MODE_EMMC		0x2
+#define MT7622_GPIO_RGMII_MODE_MASK		0x0000f000
+#define MT7622_GPIO_RGMII_MODE_SHIFT		12
+#define MT7622_GPIO_RGMII_MODE_SDCX		0x2
+#define MT7622_GPIO_SPI_MODE_MASK		0x00000f00
+#define MT7622_GPIO_SPI_MODE_SHIFT		8
+#define MT7622_GPIO_SPI_MODE_NAND		0x2
+
+#define MT7622_MSDC_INT				0x1124000C
+#define MT7622_MSDC_INT_BD_CS_ERR		0x200
+
 DECLARE_GLOBAL_DATA_PTR;
 
+static int	gpio_mode0;
+static int	msdc_int;
+
+int board_init(void)
+{
+	/*
+	 * Save content of GPIO_MODE0 as left behind by the BootROM.
+	 * Also grab MSDC1 INT status to see if BootROM has been reading
+	 * from SD card.
+	 * Together this will allow to infer the device used for booting.
+	 */
+	gpio_mode0 = readl(MT7622_GPIO_MODE0);
+	msdc_int = readl(MT7622_MSDC_INT);
+	return 0;
+}
+
 int board_late_init(void)
 {
 	struct udevice *dev;
@@ -77,3 +117,84 @@ int board_nmbm_init(void)
 
 	return 0;
 }
+
+int ft_system_setup(void *blob, struct bd_info *bd)
+{
+	bool pinctrl_set_mmc = false;
+	bool pinctrl_set_snfi = false;
+	bool pinctrl_set_emmc = false;
+	bool msdc_bd_cs_err = false;
+
+	const u32 *media_handle_p;
+	int chosen, len, ret;
+	const char *media;
+	u32 media_handle, strap;
+
+	if ((gpio_mode0 & MT7622_GPIO_RGMII_MODE_MASK) >>
+	    MT7622_GPIO_RGMII_MODE_SHIFT == MT7622_GPIO_RGMII_MODE_SDCX)
+		pinctrl_set_mmc = true;
+
+	if ((gpio_mode0 & MT7622_GPIO_SPI_MODE_MASK) >>
+	    MT7622_GPIO_SPI_MODE_SHIFT == MT7622_GPIO_SPI_MODE_NAND)
+		pinctrl_set_snfi = true;
+
+	if ((gpio_mode0 & MT7622_GPIO_NAND_MODE_MASK) >>
+	    MT7622_GPIO_NAND_MODE_SHIFT == MT7622_GPIO_NAND_MODE_EMMC)
+		pinctrl_set_emmc = true;
+
+	if (msdc_int & MT7622_MSDC_INT_BD_CS_ERR)
+		msdc_bd_cs_err = true;
+
+	strap = readl(MT7622_TOPRGUSTRAP_PAR);
+	strap &= MT7622_BOOT_SEQ_MASK;
+	strap >>= MT7622_BOOT_SEQ_SHIFT;
+	switch (strap) {
+	case MT7622_BOOT_SEQ_NOR_EMMC_SDXC:
+		if (!pinctrl_set_emmc)
+			media = "rootdisk-nor";
+		else if (pinctrl_set_mmc)
+			media = "rootdisk-emmc";
+		else
+			media = "rootdisk-sd";
+		break
+		;;
+	case MT7622_BOOT_SEQ_SPI_NAND_EMMC_SDXC:
+		if (pinctrl_set_snfi)
+			media = "rootdisk-snfi";
+		else if (pinctrl_set_emmc)
+			media = "rootdisk-emmc";
+		else
+			media = "rootdisk-sd";
+		break
+		;;
+	case MT7622_BOOT_SEQ_NAND_EMMC_SDXC:
+	case MT7622_BOOT_SEQ_SDXC_EMMC_NAND:
+		if (!pinctrl_set_emmc && pinctrl_set_mmc)
+			media = "rootdisk-nand";
+		else if (pinctrl_set_emmc)
+			media = "rootdisk-emmc";
+		else
+			media = "rootdisk-sd";
+		break
+		;;
+	}
+
+	chosen = fdt_path_offset(blob, "/chosen");
+	if (chosen <= 0)
+		return 0;
+
+	media_handle_p = fdt_getprop(blob, chosen, media, &len);
+	if (media_handle_p <= 0 || len != 4)
+		return 0;
+
+	media_handle = *media_handle_p;
+	ret = fdt_setprop(blob, chosen, "rootdisk", &media_handle, sizeof(media_handle));
+	if (ret) {
+		printf("cannot set media phandle %s as rootdisk /chosen node\n", media);
+		return ret;
+	}
+
+	printf("set /chosen/rootdisk to bootrom media: %s (phandle 0x%08x)\n", media, fdt32_to_cpu(media_handle));
+
+	return 0;
+}
--- a/configs/mt7622_rfb_defconfig
+++ b/configs/mt7622_rfb_defconfig
@@ -16,7 +16,6 @@ CONFIG_DEFAULT_FDT_FILE="mt7622-rfb"
 CONFIG_SYS_PBSIZE=1049
 CONFIG_LOGLEVEL=7
 CONFIG_LOG=y
-# CONFIG_BOARD_INIT is not set
 CONFIG_SYS_PROMPT="MT7622> "
 CONFIG_SYS_MAXARGS=8
 CONFIG_CMD_BOOTMENU=y
