diff --git a/mdb.c b/mdb.c
index 6a31b56b..082e823e 100644
--- a/mdb.c
+++ b/mdb.c
@@ -10204,8 +10204,11 @@ int mdb_dbi_open(MDB_txn *txn, const char *name, unsigned flags, MDB_dbi *dbi)
 		MDB_node *node = NODEPTR(mc.mc_pg[mc.mc_top], mc.mc_ki[mc.mc_top]);
 		if (unlikely((node->mn_flags & (F_DUPDATA|F_SUBDATA)) != F_SUBDATA))
 			return MDB_INCOMPATIBLE;
-	} else if (! (rc == MDB_NOTFOUND && (flags & MDB_CREATE))) {
-		return rc;
+	} else {
+		if (rc != MDB_NOTFOUND || !(flags & MDB_CREATE))
+			return rc;
+		if (F_ISSET(txn->mt_flags, MDB_TXN_RDONLY))
+			return EACCES;
 	}
 
 	/* Done here so we cannot fail after creating a new DB */