Patch obtained from http://www.computingplugs.com/index.php/Fixing_SDHC_access_in_the_Orion/Mainline_kernel

--- a/drivers/mmc/host/mvsdio.c.orig	2009-04-14 20:51:48.000000000 +0000
+++ b/drivers/mmc/host/mvsdio.c	2009-04-19 15:58:42.261724324 +0000
@@ -21,6 +21,7 @@
 #include <linux/irq.h>
 #include <linux/gpio.h>
 #include <linux/mmc/host.h>
+#include <linux/mmc/sd.h>
 
 #include <asm/sizes.h>
 #include <asm/unaligned.h>
@@ -123,6 +124,7 @@
 
 	dev_dbg(host->dev, "cmd %d (hw state 0x%04x)\n",
 		cmd->opcode, mvsd_read(MVSD_HW_STATE));
+	if (cmd->opcode == SD_SWITCH) mdelay(1); /* Voodoo */
 
 	cmdreg = MVSD_CMD_INDEX(cmd->opcode);
 
@@ -620,9 +622,11 @@
 	if (ios->bus_width == MMC_BUS_WIDTH_4)
 		ctrl_reg |= MVSD_HOST_CTRL_DATA_WIDTH_4_BITS;
 
+#if 0
 	if (ios->timing == MMC_TIMING_MMC_HS ||
 	    ios->timing == MMC_TIMING_SD_HS)
 		ctrl_reg |= MVSD_HOST_CTRL_HI_SPEED_EN;
+#endif
 
 	host->ctrl = ctrl_reg;
 	mvsd_write(MVSD_HOST_CTRL, ctrl_reg);
--- kernel/drivers/mmc/core/core.c.orig	2009-04-14 20:51:48.000000000 +0000
+++ kernel/drivers/mmc/core/core.c	2009-04-19 17:36:35.985746917 +0000
@@ -286,9 +286,9 @@
 			 * The limit is really 250 ms, but that is
 			 * insufficient for some crappy cards.
 			 */
-			limit_us = 300000;
+			limit_us = 500000;
 		else
-			limit_us = 100000;
+			limit_us = 200000;
 
 		/*
 		 * SDHC cards always use these fixed values.