diff --git a/litex/soc/software/bios/sdcard.c b/litex/soc/software/bios/sdcard.c
index a732e063e..c12b2db17 100644
--- a/litex/soc/software/bios/sdcard.c
+++ b/litex/soc/software/bios/sdcard.c
@@ -70,7 +70,7 @@ void sdclk_set_clk(unsigned int freq) {
 	while(!(sdclk_status_read() & CLKGEN_STATUS_LOCKED));
 }
 
-#else
+#elif CSR_SDCLK_MMCM_DRP_WRITE_ADDR
 
 static void sdclk_mmcm_write(unsigned int adr, unsigned int data) {
 	sdclk_mmcm_drp_adr_write(adr);
@@ -133,6 +133,12 @@ void sdclk_set_clk(unsigned int freq) {
 	sdclk_set_config(clk_m, clk_d);
 }
 
+#else
+
+void sdclk_set_clk(unsigned int freq) {
+	printf("Unimplemented!\n");
+}
+
 #endif
 
 /* command utils */