diff --git a/lib/i2s.toit b/lib/i2s.toit
index 27ab8bb6d..676bb9e82 100644
--- a/lib/i2s.toit
+++ b/lib/i2s.toit
@@ -50,7 +50,6 @@ class Bus:
       --use_apll/bool=false
       --buffer_size/int=(32 * 2 * bits_per_sample / 8):
     if buffer_size % (2 * bits_per_sample / 8) != 0: throw "INVALID_ARGUMENT"
-    if mclk and mclk.num != 0 and mclk.num != 1 and mclk.num != 3: throw "INVALID_ARGUMENT"
     sck_pin := sck ? sck.num : -1
     ws_pin := ws ? ws.num : -1
     tx_pin := tx ? tx.num : -1