diff --git a/os/src/drivers/sd_card/exynos5/dwmmc.h b/os/src/drivers/sd_card/exynos5/dwmmc.h
index 308f3cbc23..7012c57483 100644
--- a/os/src/drivers/sd_card/exynos5/dwmmc.h
+++ b/os/src/drivers/sd_card/exynos5/dwmmc.h
@@ -383,16 +383,28 @@ struct Exynos5_msh_controller : private Dwmmc, Sd_card::Host_controller
 			}
 
 			Card_info card_info = _detect_mmc();
-#if 0
-			/* set to eight bit transfer Bit */
-			if (!setup_bus(CLK_DIV_52Mhz, _delayer))
+
+			/* switch frequency to high speed */
+			enum { EXT_CSD_HS_TIMING = 185 };
+			if (!issue_command(Mmc_switch(EXT_CSD_HS_TIMING, 1))) {
+				PERR("Error setting high speed frequency");
 				throw Detection_failed();
+			}
+
+			enum { EXT_CSD_BUS_WIDTH = 183 };
+			/* set card to 8 bit */
+			if (!issue_command(Mmc_switch(EXT_CSD_BUS_WIDTH, 2))) {
+				PERR("Error setting card bus width");
+				throw Detection_failed();
+			}
 
 			bus_width(BUS_WIDTH_8);
-			/*
-			 * TODO SD card: set bus width (on card) - 4 bit
-			 */
-#endif
+
+			/* set to eight bit transfer Bit */
+			if (!setup_bus(CLK_DIV_52Mhz, _delayer)) {
+				PERR("Error setting bus to high speed");
+				throw Detection_failed();
+			}
 
 			/*
 			 * Enable Interrupts data read timeout | data transfer done | response
diff --git a/os/src/drivers/sd_card/sd_card.h b/os/src/drivers/sd_card/sd_card.h
index f926545ef0..92f926fc81 100644
--- a/os/src/drivers/sd_card/sd_card.h
+++ b/os/src/drivers/sd_card/sd_card.h
@@ -227,6 +227,25 @@ namespace Sd_card {
 		}
 	};
 
+	struct Mmc_switch : Command<6, RESPONSE_48_BIT>
+	{
+		enum { SWITCH_MODE_WRITE_BYTE = 0x3 };
+
+		struct Arg : Sd_card::Arg
+		{
+			struct Value : Bitfield<8,  8> { };
+			struct Index : Bitfield<16, 8> { };
+			struct Mode  : Bitfield<24, 8> { };
+		};
+
+		Mmc_switch(unsigned index, unsigned val)
+		{
+			Arg::Mode::set(arg,  SWITCH_MODE_WRITE_BYTE);
+			Arg::Index::set(arg, index);
+			Arg::Value::set(arg, val);
+		}
+	};
+
 	struct Sd_send_op_cond : Prefixed_command<41, RESPONSE_48_BIT>
 	{
 		struct Arg : Sd_card::Arg