diff --git a/drivers/mmc/mmc.c b/drivers/mmc/mmc.c
index be211016cf5df42e95e8365ae5a8ccdde61889d2..16a7a90398fa33e1841d36d73088fdb4d8ad8ee0 100644
--- a/drivers/mmc/mmc.c
+++ b/drivers/mmc/mmc.c
@@ -1065,7 +1065,9 @@ static int mmc_startup(struct mmc *mmc)
 				return err;
 			else
 				ext_csd[EXT_CSD_ERASE_GROUP_DEF] = 1;
+		}
 
+		if (ext_csd[EXT_CSD_ERASE_GROUP_DEF] & 0x01) {
 			/* Read out group size from ext_csd */
 			mmc->erase_grp_size =
 				ext_csd[EXT_CSD_HC_ERASE_GRP_SIZE] * 1024;
@@ -1092,6 +1094,10 @@ static int mmc_startup(struct mmc *mmc)
 			mmc->erase_grp_size = (erase_gsz + 1)
 				* (erase_gmul + 1);
 		}
+
+		mmc->hc_wp_grp_size = 1024
+			* ext_csd[EXT_CSD_HC_ERASE_GRP_SIZE]
+			* ext_csd[EXT_CSD_HC_WP_GRP_SIZE];
 	}
 
 	err = mmc_set_capacity(mmc, mmc->part_num);
diff --git a/include/mmc.h b/include/mmc.h
index 6c8bbfc952b4184349010c29a9391cc7c204bcb8..bcaf9f012f0891d664eb7632a530b5c97c9760a4 100644
--- a/include/mmc.h
+++ b/include/mmc.h
@@ -316,6 +316,7 @@ struct mmc {
 	uint read_bl_len;
 	uint write_bl_len;
 	uint erase_grp_size;	/* in 512-byte sectors */
+	uint hc_wp_grp_size;	/* in 512-byte sectors */
 	u64 capacity;
 	u64 capacity_user;
 	u64 capacity_boot;