diff --git a/include/sdcard.h b/include/sdcard.h
index 1f2b0bca..4b1145eb 100644
--- a/include/sdcard.h
+++ b/include/sdcard.h
@@ -33,6 +33,10 @@
 #elif HAS_SDCARD == 2 // MMC interface
 #include "driver/sdmmc_host.h"
 
+#ifndef SDCARD_SLOTCONFIG
+#define SDCARD_SLOTCONFIG SDMMC_SLOT_CONFIG_DEFAULT()
+#endif
+
 #ifndef SDCARD_SLOTWIDTH
 #define SDCARD_SLOTWIDTH 1
 #endif
diff --git a/src/sdcard.cpp b/src/sdcard.cpp
index d4c23e46..54414233 100644
--- a/src/sdcard.cpp
+++ b/src/sdcard.cpp
@@ -132,7 +132,7 @@ bool sdcard_init(bool create) {
   // has these signals.
   // Default config for SDMMC_HOST_DEFAULT (4-bit bus width, slot 1)
   // https://docs.espressif.com/projects/esp-idf/en/latest/esp32/api-reference/peripherals/sdmmc_host.html
-  sdmmc_slot_config_t slot_config = SDMMC_SLOT_CONFIG_DEFAULT();
+  sdmmc_slot_config_t slot_config = SDCARD_SLOTCONFIG;
 
   // Set 1-line or 4-line SD mode (default is 1-line)
   slot_config.width = SDCARD_SLOTWIDTH;