diff --git a/liteeth/test/model/udp.py b/liteeth/test/model/udp.py
index 2f82f9652..c76853ee9 100644
--- a/liteeth/test/model/udp.py
+++ b/liteeth/test/model/udp.py
@@ -40,6 +40,7 @@ class UDPPacket(Packet):
 class UDP(Module):
 	def  __init__(self, ip, ip_address, debug=False, loopback=False):
 		self.ip = ip
+		self.ip_address = ip_address
 		self.debug = debug
 		self.loopback = loopback
 		self.tx_packets = []
@@ -63,8 +64,10 @@ class UDP(Module):
 		ip_packet.flags = 0
 		ip_packet.fragment_offset = 0
 		ip_packet.time_to_live = 0x80
-		ip_packet.source_ip_address = ip_address,
+		ip_packet.source_ip_address = self.ip_address
 		ip_packet.destination_ip_address = 0x12345678 # XXX
+		ip_packet.header_checksum = 0
+		ip_packet.protocol = udp_protocol
 		self.ip.send(ip_packet)
 
 	def callback(self, packet):
diff --git a/liteeth/test/udpip_tb.py b/liteeth/test/udpip_tb.py
index 10fd7e196..e0a0549a5 100644
--- a/liteeth/test/udpip_tb.py
+++ b/liteeth/test/udpip_tb.py
@@ -14,20 +14,22 @@ mac_address = 0x12345678abcd
 
 class TB(Module):
 	def __init__(self):
-		self.submodules.phy_model = phy.PHY(8, debug=True)
-		self.submodules.mac_model = mac.MAC(self.phy_model, debug=True, loopback=False)
-		self.submodules.arp_model = arp.ARP(self.mac_model, mac_address, ip_address, debug=True)
-		self.submodules.ip_model = ip.IP(self.mac_model, mac_address, ip_address, debug=True, loopback=False)
-		self.submodules.udp_model = udp.UDP(self.ip_model, ip_address, debug=True, loopback=False)
+		self.submodules.phy_model = phy.PHY(8, debug=False)
+		self.submodules.mac_model = mac.MAC(self.phy_model, debug=False, loopback=False)
+		self.submodules.arp_model = arp.ARP(self.mac_model, mac_address, ip_address, debug=False)
+		self.submodules.ip_model = ip.IP(self.mac_model, mac_address, ip_address, debug=False, loopback=False)
+		self.submodules.udp_model = udp.UDP(self.ip_model, ip_address, debug=False, loopback=True)
 
 		self.submodules.udp_ip = LiteEthUDPIPCore(self.phy_model, mac_address, ip_address)
 		self.submodules.streamer = PacketStreamer(eth_udp_user_description(8))
+		self.submodules.logger = PacketLogger(eth_udp_user_description(8))
 		self.comb += [
 			Record.connect(self.streamer.source, self.udp_ip.sink),
 			self.udp_ip.sink.ip_address.eq(0x12345678),
 			self.udp_ip.sink.source_port.eq(0x1234),
 			self.udp_ip.sink.destination_port.eq(0x5678),
-			self.udp_ip.sink.length.eq(64)
+			self.udp_ip.sink.length.eq(64),
+			Record.connect(self.udp_ip.source, self.logger.sink)
 		]
 
 		# use sys_clk for each clock_domain
@@ -53,6 +55,12 @@ class TB(Module):
 		while True:
 			packet = Packet([i for i in range(64)])
 			yield from self.streamer.send(packet)
+			yield from self.logger.receive()
+
+			# check results
+			s, l, e = check(packet, self.logger.packet)
+			print("shift "+ str(s) + " / length " + str(l) + " / errors " + str(e))
+
 
 if __name__ == "__main__":
 	run_simulation(TB(), ncycles=2048, vcd_name="my.vcd", keep_files=True)