diff --git a/tb/test_ip_eth_rx.py b/tb/test_ip_eth_rx.py
index 08fc0f497..168fc63ea 100755
--- a/tb/test_ip_eth_rx.py
+++ b/tb/test_ip_eth_rx.py
@@ -363,6 +363,7 @@ def bench():
 
                 yield wait()
 
+                yield clk.posedge
                 yield clk.posedge
                 yield clk.posedge
 
@@ -426,6 +427,7 @@ def bench():
 
                 yield wait()
 
+                yield clk.posedge
                 yield clk.posedge
                 yield clk.posedge
 
@@ -497,6 +499,7 @@ def bench():
 
                 yield wait()
 
+                yield clk.posedge
                 yield clk.posedge
                 yield clk.posedge
 
@@ -569,6 +572,7 @@ def bench():
 
                 yield wait()
 
+                yield clk.posedge
                 yield clk.posedge
                 yield clk.posedge
 
@@ -640,6 +644,7 @@ def bench():
 
                 yield wait()
 
+                yield clk.posedge
                 yield clk.posedge
                 yield clk.posedge
 
@@ -712,6 +717,7 @@ def bench():
 
                 yield wait()
 
+                yield clk.posedge
                 yield clk.posedge
                 yield clk.posedge
 
@@ -785,6 +791,7 @@ def bench():
 
                 yield wait()
 
+                yield clk.posedge
                 yield clk.posedge
                 yield clk.posedge
 
@@ -859,6 +866,7 @@ def bench():
 
                 yield wait()
 
+                yield clk.posedge
                 yield clk.posedge
                 yield clk.posedge
 
@@ -933,6 +941,7 @@ def bench():
 
                 yield wait()
 
+                yield clk.posedge
                 yield clk.posedge
                 yield clk.posedge
 
@@ -1005,6 +1014,7 @@ def bench():
 
                 yield wait()
 
+                yield clk.posedge
                 yield clk.posedge
                 yield clk.posedge
 
@@ -1072,6 +1082,7 @@ def bench():
 
                 yield wait()
 
+                yield clk.posedge
                 yield clk.posedge
                 yield clk.posedge
 
@@ -1087,7 +1098,7 @@ def bench():
 
                 yield delay(100)
 
-        for length in range(1,20):
+        for length in range(1,21):
             yield clk.posedge
             print("test 12: truncated header, length %d" % length)
             current_test.next = 12
@@ -1142,6 +1153,7 @@ def bench():
 
                 yield wait()
 
+                yield clk.posedge
                 yield clk.posedge
                 yield clk.posedge
 
diff --git a/tb/test_ip_eth_tx.py b/tb/test_ip_eth_tx.py
index 9ae3f7453..2ef007d4c 100755
--- a/tb/test_ip_eth_tx.py
+++ b/tb/test_ip_eth_tx.py
@@ -326,6 +326,7 @@ def bench():
 
                 yield wait()
 
+                yield clk.posedge
                 yield clk.posedge
                 yield clk.posedge
 
@@ -389,6 +390,7 @@ def bench():
 
                 yield wait()
 
+                yield clk.posedge
                 yield clk.posedge
                 yield clk.posedge
 
@@ -463,6 +465,7 @@ def bench():
 
                 yield wait()
 
+                yield clk.posedge
                 yield clk.posedge
                 yield clk.posedge
 
@@ -539,6 +542,7 @@ def bench():
 
                 yield wait()
 
+                yield clk.posedge
                 yield clk.posedge
                 yield clk.posedge
 
@@ -614,6 +618,7 @@ def bench():
 
                 yield wait()
 
+                yield clk.posedge
                 yield clk.posedge
                 yield clk.posedge
 
@@ -690,6 +695,7 @@ def bench():
 
                 yield wait()
 
+                yield clk.posedge
                 yield clk.posedge
                 yield clk.posedge
 
@@ -767,6 +773,7 @@ def bench():
 
                 yield wait()
 
+                yield clk.posedge
                 yield clk.posedge
                 yield clk.posedge
 
@@ -845,6 +852,7 @@ def bench():
 
                 yield wait()
 
+                yield clk.posedge
                 yield clk.posedge
                 yield clk.posedge
 
@@ -920,6 +928,7 @@ def bench():
 
                 yield wait()
 
+                yield clk.posedge
                 yield clk.posedge
                 yield clk.posedge