diff --git a/board/toradex/verdin-imx8mm/spl.c b/board/toradex/verdin-imx8mm/spl.c
index 685ac94..fb9aae6 100644
--- a/board/toradex/verdin-imx8mm/spl.c
+++ b/board/toradex/verdin-imx8mm/spl.c
@@ -34,14 +34,11 @@
 int spl_board_boot_device(enum boot_device boot_dev_spl)
 {
 	switch (boot_dev_spl) {
-	case MMC1_BOOT:
+	case MMC1_BOOT: /* eMMC */
 		return BOOT_DEVICE_MMC1;
-	case SD2_BOOT:
+	case SD2_BOOT: /* SD card */
 	case MMC2_BOOT:
 		return BOOT_DEVICE_MMC2;
-	case SD3_BOOT:
-	case MMC3_BOOT:
-		return BOOT_DEVICE_MMC1;
 	case USB_BOOT:
 		return BOOT_DEVICE_BOARD;
 	default:
@@ -83,7 +80,6 @@
 }
 #endif
 
-
 __weak void board_early_init(void)
 {
 	init_uart_clk(0);