diff -uprN -X linux-2.6.32.3/Documentation/dontdiff linux-2.6.32.3-vanilla/drivers/mmc/host/at91_mci.c linux-2.6.32.3/drivers/mmc/host/at91_mci.c
--- linux-2.6.32.3-vanilla/drivers/mmc/host/at91_mci.c	2010-01-06 17:07:45.000000000 -0600
+++ linux-2.6.32.3/drivers/mmc/host/at91_mci.c	2010-09-17 10:42:23.000000000 -0500
@@ -1017,7 +1017,7 @@ static int __init at91_mci_probe(struct 
 	host->bus_mode = 0;
 	host->board = pdev->dev.platform_data;
 	if (host->board->wire4) {
-		if (cpu_is_at91sam9260() || cpu_is_at91sam9263())
+		if (cpu_is_at91sam9260() || cpu_is_at91sam9g20() || cpu_is_at91sam9263())
 			mmc->caps |= MMC_CAP_4_BIT_DATA;
 		else
 			dev_warn(&pdev->dev, "4 wire bus mode not supported"