diff --git a/sys/dev/mmc/mmcsd.c b/sys/dev/mmc/mmcsd.c
index 8e08b6326c73..af2a88e2af47 100644
--- a/sys/dev/mmc/mmcsd.c
+++ b/sys/dev/mmc/mmcsd.c
@@ -135,6 +135,8 @@ mmcsd_attach(device_t dev)
 	d->d_maxsize = 4*1024*1024;	/* Maximum defined SD card AU size. */
 	d->d_sectorsize = mmc_get_sector_size(dev);
 	d->d_mediasize = mmc_get_media_size(dev) * d->d_sectorsize;
+	d->d_stripeoffset = 0;
+	d->d_stripesize = mmc_get_erase_sector(dev) * d->d_sectorsize;
 	d->d_unit = device_get_unit(dev);
 	d->d_flags = DISKFLAG_CANDELETE;
 	/*