diff --git a/liteeth/phy/s6rgmii.py b/liteeth/phy/s6rgmii.py
index 30fd33a..8d76b6e 100644
--- a/liteeth/phy/s6rgmii.py
+++ b/liteeth/phy/s6rgmii.py
@@ -59,6 +59,8 @@ class LiteEthPHYRGMIIRX(Module):
         rx_ctl_d = Signal()
         self.sync += rx_ctl_d.eq(rx_ctl)
 
+        last = Signal()
+        self.comb += last.eq(~rx_ctl & rx_ctl_d)
         self.sync += [
             source.valid.eq(rx_ctl),
             source.data.eq(rx_data)