diff --git a/ports/stm32/sdcard.c b/ports/stm32/sdcard.c
index cdec576dc2..12c9eb4446 100644
--- a/ports/stm32/sdcard.c
+++ b/ports/stm32/sdcard.c
@@ -200,6 +200,14 @@ void sdcard_init(void) {
     #endif
 }
 
+void sdcard_select_sd(void) {
+    pyb_sdmmc_flags |= PYB_SDMMC_FLAG_SD;
+}
+
+void sdcard_select_mmc(void) {
+    pyb_sdmmc_flags |= PYB_SDMMC_FLAG_MMC;
+}
+
 STATIC void sdmmc_msp_init(void) {
     // enable SDIO clock
     SDMMC_CLK_ENABLE();
diff --git a/ports/stm32/sdcard.h b/ports/stm32/sdcard.h
index e436ffffe1..a2e4e4517c 100644
--- a/ports/stm32/sdcard.h
+++ b/ports/stm32/sdcard.h
@@ -30,6 +30,8 @@
 #define SDCARD_BLOCK_SIZE (512)
 
 void sdcard_init(void);
+void sdcard_select_sd(void);
+void sdcard_select_mmc(void);
 bool sdcard_is_present(void);
 bool sdcard_power_on(void);
 void sdcard_power_off(void);