diff --git a/liteeth/mac/padding.py b/liteeth/mac/padding.py
index 2432873..ac9f644 100644
--- a/liteeth/mac/padding.py
+++ b/liteeth/mac/padding.py
@@ -14,12 +14,14 @@ from liteeth.common import *
 
 class LiteEthMACPaddingInserter(Module):
     def __init__(self, dw, padding):
+        assert dw in [8, 16, 32, 64]
         self.sink   = sink   = stream.Endpoint(eth_phy_description(dw))
         self.source = source = stream.Endpoint(eth_phy_description(dw))
 
         # # #
 
         padding_limit = math.ceil(padding/(dw/8))-1
+        last_be       = 2**((padding-1)%(dw//8))
 
         counter      = Signal(16)
         counter_done = Signal()
@@ -33,8 +35,14 @@ class LiteEthMACPaddingInserter(Module):
                 If(sink.last,
                     If(~counter_done,
                         source.last.eq(0),
+                        source.last_be.eq(0),
                         NextState("PADDING")
-                    ).Else(
+                    ).Elif((counter == padding_limit) & (last_be > sink.last_be),
+                        # If the right amount of data words are transmitted, but
+                        # too few bytes, transmit more bytes of the word. The
+                        # formerly "unused" bytes get transmitted as well
+                        source.last_be.eq(last_be)
+                    ). Else(
                         NextValue(counter, 0),
                     )
                 )
@@ -42,7 +50,9 @@ class LiteEthMACPaddingInserter(Module):
         )
         fsm.act("PADDING",
             source.valid.eq(1),
-            source.last.eq(counter_done),
+            If(counter_done,
+                source.last_be.eq(last_be),
+                source.last.eq(1)),
             source.data.eq(0),
             If(source.valid & source.ready,
                 NextValue(counter, counter + 1),