diff --git a/bootloader/libs/fatfs/diskio.c b/bootloader/libs/fatfs/diskio.c
index 803dc91..8aed635 100644
--- a/bootloader/libs/fatfs/diskio.c
+++ b/bootloader/libs/fatfs/diskio.c
@@ -46,16 +46,7 @@ DRESULT disk_read (
 	UINT count		/* Number of sectors to read */
 )
 {
-	// Ensure that buffer resides in DRAM and it's DMA aligned.
-	if (((u32)buff >= DRAM_START) && !((u32)buff % 8))
-		return sdmmc_storage_read(&sd_storage, sector, count, buff) ? RES_OK : RES_ERROR;
-	u8 *buf = (u8 *)SDMMC_UPPER_BUFFER;
-	if (sdmmc_storage_read(&sd_storage, sector, count, buf))
-	{
-		memcpy(buff, buf, 512 * count);
-		return RES_OK;
-	}
-	return RES_ERROR;
+	return sdmmc_storage_read(&sd_storage, sector, count, buff) ? RES_OK : RES_ERROR;
 }
 
 /*-----------------------------------------------------------------------*/
@@ -68,14 +59,7 @@ DRESULT disk_write (
 	UINT count			/* Number of sectors to write */
 )
 {
-	// Ensure that buffer resides in DRAM and it's DMA aligned.
-	if (((u32)buff >= DRAM_START) && !((u32)buff % 8))
-		return sdmmc_storage_write(&sd_storage, sector, count, (void *)buff) ? RES_OK : RES_ERROR;
-	u8 *buf = (u8 *)SDMMC_UPPER_BUFFER;
-	memcpy(buf, buff, 512 * count);
-	if (sdmmc_storage_write(&sd_storage, sector, count, buf))
-		return RES_OK;
-	return RES_ERROR;
+	return sdmmc_storage_write(&sd_storage, sector, count, (void *)buff) ? RES_OK : RES_ERROR;
 }
 
 /*-----------------------------------------------------------------------*/
diff --git a/bootloader/storage/sdmmc.c b/bootloader/storage/sdmmc.c
index 6168784..fc941c8 100644
--- a/bootloader/storage/sdmmc.c
+++ b/bootloader/storage/sdmmc.c
@@ -202,12 +202,34 @@ DPRINTF("readwrite: %08X\n", blkcnt);
 
 int sdmmc_storage_read(sdmmc_storage_t *storage, u32 sector, u32 num_sectors, void *buf)
 {
-	return _sdmmc_storage_readwrite(storage, sector, num_sectors, buf, 0);
+	// Ensure that buffer resides in DRAM and it's DMA aligned.
+	if (((u32)buf >= DRAM_START) && !((u32)buf % 8))
+		return _sdmmc_storage_readwrite(storage, sector, num_sectors, buf, 0);
+
+	if (num_sectors > (SDMMC_UP_BUF_SZ / 512))
+		return 0;
+
+	u8 *tmp_buf = (u8 *)SDMMC_UPPER_BUFFER;
+	if (_sdmmc_storage_readwrite(storage, sector, num_sectors, tmp_buf, 0))
+	{
+		memcpy(buf, tmp_buf, 512 * num_sectors);
+		return 1;
+	}
+	return 0;
 }
 
 int sdmmc_storage_write(sdmmc_storage_t *storage, u32 sector, u32 num_sectors, void *buf)
 {
-	return _sdmmc_storage_readwrite(storage, sector, num_sectors, buf, 1);
+	// Ensure that buffer resides in DRAM and it's DMA aligned.
+	if (((u32)buf >= DRAM_START) && !((u32)buf % 8))
+		return _sdmmc_storage_readwrite(storage, sector, num_sectors, buf, 1);
+
+	if (num_sectors > (SDMMC_UP_BUF_SZ / 512))
+		return 0;
+
+	u8 *tmp_buf = (u8 *)SDMMC_UPPER_BUFFER;
+	memcpy(tmp_buf, buf, 512 * num_sectors);
+	return _sdmmc_storage_readwrite(storage, sector, num_sectors, tmp_buf, 1);
 }
 
 /*
diff --git a/nyx/nyx_gui/libs/fatfs/diskio.c b/nyx/nyx_gui/libs/fatfs/diskio.c
index cdeebf9..22cf3fd 100644
--- a/nyx/nyx_gui/libs/fatfs/diskio.c
+++ b/nyx/nyx_gui/libs/fatfs/diskio.c
@@ -44,16 +44,7 @@ DRESULT disk_read (
 	UINT count		/* Number of sectors to read */
 )
 {
-	// Ensure that buffer resides in DRAM and it's DMA aligned.
-	if (((u32)buff >= DRAM_START) && !((u32)buff % 8))
-		return sdmmc_storage_read(&sd_storage, sector, count, buff) ? RES_OK : RES_ERROR;
-	u8 *buf = (u8 *)SDMMC_UPPER_BUFFER;
-	if (sdmmc_storage_read(&sd_storage, sector, count, buf))
-	{
-		memcpy(buff, buf, 512 * count);
-		return RES_OK;
-	}
-	return RES_ERROR;
+	return sdmmc_storage_read(&sd_storage, sector, count, buff) ? RES_OK : RES_ERROR;
 }
 
 /*-----------------------------------------------------------------------*/
@@ -66,14 +57,7 @@ DRESULT disk_write (
 	UINT count			/* Number of sectors to write */
 )
 {
-	// Ensure that buffer resides in DRAM and it's DMA aligned.
-	if (((u32)buff >= DRAM_START) && !((u32)buff % 8))
-		return sdmmc_storage_write(&sd_storage, sector, count, (void *)buff) ? RES_OK : RES_ERROR;
-	u8 *buf = (u8 *)SDMMC_UPPER_BUFFER;
-	memcpy(buf, buff, 512 * count);
-	if (sdmmc_storage_write(&sd_storage, sector, count, buf))
-		return RES_OK;
-	return RES_ERROR;
+	return sdmmc_storage_write(&sd_storage, sector, count, (void *)buff) ? RES_OK : RES_ERROR;
 }
 
 /*-----------------------------------------------------------------------*/
diff --git a/nyx/nyx_gui/storage/sdmmc.c b/nyx/nyx_gui/storage/sdmmc.c
index 6c83d8b..5ce0900 100644
--- a/nyx/nyx_gui/storage/sdmmc.c
+++ b/nyx/nyx_gui/storage/sdmmc.c
@@ -202,12 +202,34 @@ DPRINTF("readwrite: %08X\n", blkcnt);
 
 int sdmmc_storage_read(sdmmc_storage_t *storage, u32 sector, u32 num_sectors, void *buf)
 {
-	return _sdmmc_storage_readwrite(storage, sector, num_sectors, buf, 0);
+	// Ensure that buffer resides in DRAM and it's DMA aligned.
+	if (((u32)buf >= DRAM_START) && !((u32)buf % 8))
+		return _sdmmc_storage_readwrite(storage, sector, num_sectors, buf, 0);
+
+	if (num_sectors > (SDMMC_UP_BUF_SZ / 512))
+		return 0;
+
+	u8 *tmp_buf = (u8 *)SDMMC_UPPER_BUFFER;
+	if (_sdmmc_storage_readwrite(storage, sector, num_sectors, tmp_buf, 0))
+	{
+		memcpy(buf, tmp_buf, 512 * num_sectors);
+		return 1;
+	}
+	return 0;
 }
 
 int sdmmc_storage_write(sdmmc_storage_t *storage, u32 sector, u32 num_sectors, void *buf)
 {
-	return _sdmmc_storage_readwrite(storage, sector, num_sectors, buf, 1);
+	// Ensure that buffer resides in DRAM and it's DMA aligned.
+	if (((u32)buf >= DRAM_START) && !((u32)buf % 8))
+		return _sdmmc_storage_readwrite(storage, sector, num_sectors, buf, 1);
+
+	if (num_sectors > (SDMMC_UP_BUF_SZ / 512))
+		return 0;
+
+	u8 *tmp_buf = (u8 *)SDMMC_UPPER_BUFFER;
+	memcpy(tmp_buf, buf, 512 * num_sectors);
+	return _sdmmc_storage_readwrite(storage, sector, num_sectors, tmp_buf, 1);
 }
 
 /*