diff --git a/experiments/src/main.rs b/experiments/src/main.rs
index 3c96cf2..c7594ad 100644
--- a/experiments/src/main.rs
+++ b/experiments/src/main.rs
@@ -91,17 +91,17 @@ pub fn main_core0() {
             Ok(_) => info!("OK!"),
             Err(a) => info!("{:?}", a),
         };
-        const SIZE: usize = 512 / 2;
+        const SIZE: usize = 512 * 2 + 1;
         let mut sd_card = result.unwrap();
-        let mut buffer: [u32; SIZE] = [0; SIZE];
+        let mut buffer: [u8; SIZE] = [0; SIZE];
         for i in 0..buffer.len() {
-            buffer[i] = (i % 16) as u32;
+            buffer[i] = (i % 16) as u8;
         }
         sd_card.write_block(0x0, 2, &mut buffer).unwrap();
         for i in 0..buffer.len() {
             buffer[i] = 0;
         }
-        sd_card.read_block(0x1, 2, &mut buffer).unwrap();
+        sd_card.read_block(0x1, 2, &mut buffer[1..]).unwrap();
         for i in 0..buffer.len() {
             info!("buffer[{}] = {}", i, buffer[i]);
         }
diff --git a/libboard_zynq/src/sdio/adma.rs b/libboard_zynq/src/sdio/adma.rs
index 3d6f4a3..9f80b7f 100644
--- a/libboard_zynq/src/sdio/adma.rs
+++ b/libboard_zynq/src/sdio/adma.rs
@@ -62,7 +62,7 @@ impl Adma2Desc32 {
     }
 }
 
-pub fn setup_adma2_descr32(sdio: &mut SDIO, blk_cnt: u32, buffer: &mut [u32]) {
+pub fn setup_adma2_descr32(sdio: &mut SDIO, blk_cnt: u32, buffer: &mut [u8]) {
     let descr_table = unsafe { &mut ADMA2_DESCR32_TABLE };
     let blk_size = sdio
         .regs
diff --git a/libboard_zynq/src/sdio/sd_card.rs b/libboard_zynq/src/sdio/sd_card.rs
index 26824f9..a58f605 100644
--- a/libboard_zynq/src/sdio/sd_card.rs
+++ b/libboard_zynq/src/sdio/sd_card.rs
@@ -143,7 +143,7 @@ impl SdCard {
         self.sdio.cmd_transfer(CMD55, self.rel_card_addr, 0)?;
         self.sdio.cmd_transfer(ACMD42, 0, 0)?;
 
-        let mut scr: [u32; 8] = [0; 8];
+        let mut scr: [u8; 32] = [0; 32];
         self.get_bus_width(&mut scr)?;
         debug!("{:?}", scr);
         if scr[1] & 0x4 != 0 {
@@ -188,9 +188,9 @@ impl SdCard {
         &mut self,
         address: u32,
         block_cnt: u16,
-        buffer: &mut [u32],
+        buffer: &mut [u8],
     ) -> Result<(), CmdTransferError> {
-        assert!(buffer.len() >= (block_cnt as usize) * (512 / 4));
+        assert!(buffer.len() >= (block_cnt as usize) * 512);
         // set block size if not set already
         if self
             .sdio
@@ -241,9 +241,9 @@ impl SdCard {
         &mut self,
         address: u32,
         block_cnt: u16,
-        buffer: &mut [u32],
+        buffer: &mut [u8],
     ) -> Result<(), CmdTransferError> {
-        assert!(buffer.len() >= (block_cnt as usize) * (512 / 4));
+        assert!(buffer.len() >= (block_cnt as usize) * 512);
         // set block size if not set already
         if self
             .sdio
@@ -287,7 +287,7 @@ impl SdCard {
         Ok(())
     }
 
-    fn get_bus_width(&mut self, buf: &mut [u32]) -> Result<(), CmdTransferError> {
+    fn get_bus_width(&mut self, buf: &mut [u8]) -> Result<(), CmdTransferError> {
         use cmd::SdCmd::*;
         debug!("Getting bus width");
         for i in 0..8 {