diff --git a/liteeth/test/etherbone_tb.py b/liteeth/test/etherbone_tb.py
index c4374d8d8..c49dc3c26 100644
--- a/liteeth/test/etherbone_tb.py
+++ b/liteeth/test/etherbone_tb.py
@@ -63,10 +63,8 @@ class TB(Module):
 		for i in range(8):
 			# test writes
 			if test_writes:
-				writes = etherbone.EtherboneWrites(base_addr=0x1000)
-				writes_data = [j for j in range(16)]
-				for write_data in writes_data:
-					writes.add(etherbone.EtherboneWrite(write_data))
+				writes_datas = [j for j in range(16)]
+				writes = etherbone.EtherboneWrites(base_addr=0x1000, datas=writes_datas)
 				record = etherbone.EtherboneRecord()
 				record.writes = writes
 				record.reads = None
@@ -77,7 +75,7 @@ class TB(Module):
 				record.wca = 0
 				record.wff = 0
 				record.byte_enable = 0xf
-				record.wcount = 16
+				record.wcount = len(writes_datas)
 				record.rcount = 0
 
 				packet = etherbone.EtherbonePacket()
@@ -88,10 +86,8 @@ class TB(Module):
 
 			# test reads
 			if test_reads:
-				reads = etherbone.EtherboneReads(base_ret_addr=0x1000)
-				reads_address = [j for j in range(16)]
-				for read_address in reads_address:
-					reads.add(etherbone.EtherboneRead(read_address))
+				reads_addrs = [j for j in range(16)]
+				reads = etherbone.EtherboneReads(base_ret_addr=0x1000, addrs=reads_addrs)
 				record = etherbone.EtherboneRecord()
 				record.writes = None
 				record.reads = reads
@@ -103,18 +99,17 @@ class TB(Module):
 				record.wff = 0
 				record.byte_enable = 0xf
 				record.wcount = 0
-				record.rcount = 16
+				record.rcount = len(reads_addrs)
 
 				packet = etherbone.EtherbonePacket()
 				packet.records = [record]
 				self.etherbone_model.send(packet)
 				yield from self.etherbone_model.receive()
-				loopback_writes_data = []
-				for write in self.etherbone_model.rx_packet.records.pop().writes.writes:
-					loopback_writes_data.append(write.data)
+				loopback_writes_datas = []
+				loopback_writes_datas = self.etherbone_model.rx_packet.records.pop().writes.get_datas()
 
 				# check results
-				s, l, e = check(writes_data, loopback_writes_data)
+				s, l, e = check(writes_datas, loopback_writes_datas)
 				print("shift "+ str(s) + " / length " + str(l) + " / errors " + str(e))
 
 if __name__ == "__main__":
diff --git a/liteeth/test/model/etherbone.py b/liteeth/test/model/etherbone.py
index 366aa5bf8..96cf49f75 100644
--- a/liteeth/test/model/etherbone.py
+++ b/liteeth/test/model/etherbone.py
@@ -24,15 +24,23 @@ class EtherboneRead:
 		return "RD32 @ 0x{:08x}".format(self.addr)
 
 class EtherboneWrites(Packet):
-	def __init__(self, init=[], base_addr=0):
+	def __init__(self, init=[], base_addr=0, datas=[]):
 		Packet.__init__(self, init)
 		self.base_addr = base_addr
 		self.writes = []
 		self.encoded = init != []
+		for data in datas:
+			self.add(EtherboneWrite(data))
 
 	def add(self, write):
 		self.writes.append(write)
 
+	def get_datas(self):
+		datas = []
+		for write in self.writes:
+			datas.append(write.data)
+		return datas
+
 	def encode(self):
 		if self.encoded:
 			raise ValueError
@@ -67,15 +75,23 @@ class EtherboneWrites(Packet):
 		return r
 
 class EtherboneReads(Packet):
-	def __init__(self, init=[], base_ret_addr=0):
+	def __init__(self, init=[], base_ret_addr=0, addrs=[]):
 		Packet.__init__(self, init)
 		self.base_ret_addr = base_ret_addr
 		self.reads = []
 		self.encoded = init != []
+		for addr in addrs:
+			self.add(EtherboneRead(addr))
 
 	def add(self, read):
 		self.reads.append(read)
 
+	def get_addrs(self):
+		addrs = []
+		for read in self.reads:
+			addrs.append(read.addr)
+		return addrs
+
 	def encode(self):
 		if self.encoded:
 			raise ValueError
@@ -301,12 +317,8 @@ class Etherbone(Module):
 
 if __name__ == "__main__":
 	# Writes/Reads
-	writes = EtherboneWrites(base_addr=0x1000)
-	for i in range(16):
-		writes.add(EtherboneWrite(i))
-	reads = EtherboneReads(base_ret_addr=0x2000)
-	for i in range(16):
-		reads.add(EtherboneRead(i))
+	writes = EtherboneWrites(base_addr=0x1000, datas=[i for i in range(16)])
+	reads = EtherboneReads(base_ret_addr=0x2000, addrs=[i for i in range(16)])
 
 	# Record
 	record = EtherboneRecord()
@@ -319,8 +331,8 @@ if __name__ == "__main__":
 	record.wca = 0
 	record.wff = 0
 	record.byte_enable = 0
-	record.wcount = 16
-	record.rcount = 16
+	record.wcount = len(writes.get_datas())
+	record.rcount = len(reads.get_addrs())
 
 	# Packet
 	packet = EtherbonePacket()