diff --git a/include/arm9/hardware/sdmmc.h b/include/arm9/hardware/sdmmc.h
index ac08efc..cb8224c 100644
--- a/include/arm9/hardware/sdmmc.h
+++ b/include/arm9/hardware/sdmmc.h
@@ -177,9 +177,8 @@
 
 static inline void setckl(uint32_t data)
 {
-	sdmmc_mask16(REG_SDCLKCTL,0x100,0);
-	sdmmc_mask16(REG_SDCLKCTL,0x2FF,data&0x2FF);
-	sdmmc_mask16(REG_SDCLKCTL,0x0,0x100);
+	sdmmc_write16(REG_SDCLKCTL, 0);
+	sdmmc_write16(REG_SDCLKCTL, 1u<<8 | (data & 0x2FF));
 }
 
 #endif
diff --git a/source/arm9/hardware/sdmmc.c b/source/arm9/hardware/sdmmc.c
index 0310937..e7c53ce 100644
--- a/source/arm9/hardware/sdmmc.c
+++ b/source/arm9/hardware/sdmmc.c
@@ -359,7 +359,7 @@
 	handleNAND.SDOPT = 0;
 	handleNAND.res = 0;
 	handleNAND.initarg = 1;
-	handleNAND.clk = 0x80;
+	handleNAND.clk = 0x10; // ~523 KHz
 	handleNAND.devicenumber = 1;
 
 	//SD
@@ -367,7 +367,7 @@
 	handleSD.SDOPT = 0;
 	handleSD.res = 0;
 	handleSD.initarg = 0;
-	handleSD.clk = 0x80;
+	handleSD.clk = 0x20; // ~261 KHz
 	handleSD.devicenumber = 0;
 
 	*(volatile uint16_t*)0x10006100 &= 0xF7FFu; //SDDATACTL32
@@ -433,8 +433,8 @@
 	if((handleNAND.error & 0x4))return -1;
 
 	handleNAND.total_size = sdmmc_calc_size((uint8_t*)&handleNAND.ret[0],0);
-	handleNAND.clk = 1;
-	setckl(1);
+	handleNAND.clk = 0; // 16.757 MHz
+	setckl(0);
 
 	sdmmc_send_command(&handleNAND,0x10407,handleNAND.initarg << 0x10);
 	if((handleNAND.error & 0x4))return -1;
@@ -497,8 +497,8 @@
 	if((handleSD.error & 0x4)) return -3;
 
 	handleSD.total_size = sdmmc_calc_size((uint8_t*)&handleSD.ret[0],-1);
-	handleSD.clk = 1;
-	setckl(1);
+	handleSD.clk = 0; // 16.757 MHz
+	setckl(0);
 
 	sdmmc_send_command(&handleSD,0x10507,handleSD.initarg << 0x10);
 	if((handleSD.error & 0x4)) return -4;