diff --git a/mibuild/sim/ethernet_tb.cpp b/mibuild/sim/ethernet_tb.cpp
new file mode 100644
index 000000000..084cf1359
--- /dev/null
+++ b/mibuild/sim/ethernet_tb.cpp
@@ -0,0 +1,296 @@
+// This file is Copyright (c) 2015 Florent Kermarrec <florent@enjoy-digital.fr>
+// License: BSD
+#include "Vdut.h"
+#include "verilated.h"
+#include "verilated_vcd_c.h"
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <sys/socket.h>
+#include <sys/ioctl.h>
+#include <termios.h>
+#include <sys/poll.h>
+
+#include <linux/if.h>
+#include <linux/if_tun.h>
+
+#define MAX(a,b) (((a)>(b))?(a):(b))
+#define MIN(a,b) (((a)<(b))?(a):(b))
+
+int trace = 0;
+
+vluint64_t main_time = 0;
+double sc_time_stamp()
+{
+	return main_time;
+}
+
+/* ios */
+
+/* Terminal functions */
+struct termios orig_termios;
+
+void reset_terminal_mode(void)
+{
+	tcsetattr(0, TCSANOW, &orig_termios);
+}
+
+void set_conio_terminal_mode(void)
+{
+	struct termios new_termios;
+
+	/* take two copies - one for now, one for later */
+	tcgetattr(0, &orig_termios);
+	memcpy(&new_termios, &orig_termios, sizeof(new_termios));
+
+	/* register cleanup handler, and set the new terminal mode */
+	atexit(reset_terminal_mode);
+	cfmakeraw(&new_termios);
+	tcsetattr(0, TCSANOW, &new_termios);
+}
+
+int kbhit(void)
+{
+	struct timeval tv = { 0L, 0L };
+	fd_set fds;
+	FD_ZERO(&fds);
+	FD_SET(0, &fds);
+	return select(1, &fds, NULL, NULL, &tv);
+}
+
+int getch(void)
+{
+	int r;
+	unsigned char c;
+	if ((r = read(0, &c, sizeof(c))) < 0) {
+		return r;
+	} else {
+		return c;
+	}
+}
+
+/* Ethernet functions */
+/* create tap:
+     openvpn --mktun --dev tap0
+     ifconfig tap0 192.168.0.14 up
+     mknod /dev/net/tap0 c 10 200
+   delete tap:
+     openvpn --rmtun --dev tap0 */
+
+unsigned char eth_txbuffer[1532];
+unsigned char eth_rxbuffer[1532];
+int eth_txbuffer_len = 0;
+int eth_rxbuffer_len = 0;
+int eth_rxbuffer_pos = 0;
+
+struct eth_device
+{
+	char *dev;
+	char *tap;
+	int fd;
+};
+
+void eth_open(struct eth_device *eth)
+{
+
+	struct ifreq ifr;
+	eth->fd = open (eth->dev, O_RDWR);
+	if(eth->fd < 0) {
+		fprintf (stderr, " Could not open dev %s\n", eth->dev);
+		return;
+	}
+
+	memset (&ifr, 0, sizeof(ifr));
+	ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
+	strncpy (ifr.ifr_name, eth->tap, IFNAMSIZ);
+
+	if (ioctl (eth->fd, TUNSETIFF, (void *) &ifr) < 0) {
+		fprintf (stderr, " Could not set %s\n", eth->tap);
+		close(eth->fd);
+	}
+	return;
+}
+
+int eth_close(struct eth_device *eth)
+{
+	if (eth->fd < 0)
+		close(eth->fd);
+}
+
+void eth_write_tap(
+	struct eth_device *eth,
+	unsigned char *buf,
+	unsigned long int length)
+{
+	write (eth->fd, buf, length);
+}
+
+int eth_read_tap (
+	struct eth_device *eth,
+	unsigned char *buf)
+{
+
+	struct pollfd fds[1];
+	int n;
+	int length;
+
+	fds[0].fd = eth->fd;
+	fds[0].events = POLLIN;
+
+	n = poll(fds, 1, 0);
+	if ((n > 0) && ((fds[0].revents & POLLIN) == POLLIN)) {
+		length = read(eth->fd, buf, 1532);
+	} else {
+		length = 0;
+	}
+	return length;
+}
+
+Vdut* dut;
+VerilatedVcdC* tfp;
+
+#define MAX_LEN 2048
+
+struct sim {
+	bool run;
+
+	unsigned int tick;
+	clock_t start;
+	clock_t end;
+	float speed;
+
+	char txbuffer[MAX_LEN];
+	char rxbuffer[MAX_LEN];
+
+	char rx_serial_stb;
+	char rx_serial_data;
+	char rx_serial_presented;
+};
+
+int console_service(struct sim *s)
+{
+	/* fpga --> console */
+	SERIAL_SOURCE_ACK = 1;
+	if(SERIAL_SOURCE_STB == 1) {
+		if (SERIAL_SOURCE_DATA == '\n')
+			putchar('\r');
+		putchar(SERIAL_SOURCE_DATA);
+		fflush(stdout);
+	}
+
+	/* console --> fpga */
+	SERIAL_SINK_STB = 0;
+	if (s->tick%(1000) == 0) {
+		if(kbhit()) {
+			char c = getch();
+			if (c == 27 && !kbhit()) {
+				printf("\r\n");
+				return -1;
+			} else {
+				SERIAL_SINK_STB = 1;
+				SERIAL_SINK_DATA = c;
+			}
+		}
+	}
+	return 0;
+}
+
+#ifdef ETH_SOURCE_STB
+int eth_last_source_stb = 0;
+
+int ethernet_service(struct eth_device *eth) {
+	/* fpga --> tap */
+	ETH_SOURCE_ACK = 1;
+	if(ETH_SOURCE_STB == 1) {
+		eth_txbuffer[eth_txbuffer_len] = ETH_SOURCE_DATA;
+		eth_txbuffer_len++;
+	} else {
+		if (eth_last_source_stb) {
+			eth_write_tap(eth, eth_txbuffer, eth_txbuffer_len-1); // XXX FIXME software or gateware?
+			eth_txbuffer_len = 0;
+		}
+	}
+	eth_last_source_stb = ETH_SOURCE_STB;
+
+	/* tap --> fpga */
+	if (eth_rxbuffer_len == 0) {
+		ETH_SINK_STB = 0;
+		eth_rxbuffer_pos = 0;
+		eth_rxbuffer_len = eth_read_tap(eth, eth_rxbuffer);
+	} else {
+		if (eth_rxbuffer_pos < MAX(eth_rxbuffer_len, 60)) {
+			ETH_SINK_STB = 1;
+			ETH_SINK_DATA = eth_rxbuffer[eth_rxbuffer_pos];
+			eth_rxbuffer_pos++;
+		} else {
+			ETH_SINK_STB = 0;
+			eth_rxbuffer_len = 0;
+			memset(eth_rxbuffer, 0, 1532);
+		}
+	}
+}
+#endif
+
+void sim_tick(struct sim *s)
+{
+	SYS_CLK = s->tick%2;
+	dut->eval();
+	if (trace)
+		tfp->dump(s->tick);
+	s->tick++;
+}
+
+void sim_init(struct sim *s)
+{
+	int i;
+	s->tick = 0;
+#ifdef SYS_RST
+	SYS_RST = 1;
+	SYS_CLK = 0;
+	for (i=0; i<8; i++)
+		sim_tick(s);
+	SYS_RST = 0;
+#endif
+	s->start = clock();
+}
+
+int main(int argc, char **argv, char **env)
+{
+	Verilated::commandArgs(argc, argv);
+	dut = new Vdut;
+
+	Verilated::traceEverOn(true);
+	tfp = new VerilatedVcdC;
+	dut->trace(tfp, 99);
+	tfp->open("dut.vcd");
+
+	struct sim s;
+	sim_init(&s);
+
+	struct eth_device eth;
+	char dev[] = "/dev/net/tap0";
+	char tap[] = "tap0";
+	eth.dev = dev;
+	eth.tap = tap;
+	eth_open(&eth);
+
+	s.run = true;
+	while(s.run) {
+		sim_tick(&s);
+		if (SYS_CLK) {
+			if (console_service(&s) != 0)
+				s.run = false;
+#ifdef ETH_SOURCE_STB
+			ethernet_service(&eth);
+#endif
+		}
+	}
+	s.end = clock();
+
+	tfp->close();
+
+	exit(0);
+}
diff --git a/mibuild/sim/server.py b/mibuild/sim/server.py
deleted file mode 100644
index 87981fca1..000000000
--- a/mibuild/sim/server.py
+++ /dev/null
@@ -1,129 +0,0 @@
-# This file is Copyright (c) 2015 Florent Kermarrec <florent@enjoy-digital.fr>
-# License: BSD
-
-import socket
-import os
-import pty
-import time
-import threading
-import subprocess
-import struct
-import fcntl
-
-messages= {
-	"EXIT":		0,
-	"ACK":		1,
-	"ERROR": 	2,
-	"UART": 	3,
-	"ETHERNET":	4
-}
-
-class PacketTooLarge(Exception):
-	pass
-
-class VerilatorServer:
-	def __init__(self, sockaddr="/tmp/simsocket"):
-		self.sockaddr = sockaddr
-		self.socket = socket.socket(socket.AF_UNIX, socket.SOCK_SEQPACKET)
-		self._cleanup_file()
-		self.socket.bind(self.sockaddr)
-		self.socket.listen(1)
-
-		master, slave = pty.openpty()
-		self.serial = master
-		self.serial_name = os.ttyname(slave)
-
-		os.system("openvpn --mktun --dev tap0")
-		os.system("ip link set tap0 up")
-		os.system("ip addr add 192.169.0.14/24 dev tap0")
-		os.system("iface tap0 inet")
-		os.system("mknod /dev/net/tap c 10 200")
-		os.system("chmod 600 /dev/net/tap")
-
-
-		self.ack = False
-
-		self._print_banner()
-
-	def _print_banner(self):
-		print("Mibuild simulation server")
-		print("sockaddr: {}".format(self.sockaddr))
-		print("serial: {}".format(self.serial_name))
-
-	def _cleanup_file(self):
-		try:
-			os.remove(self.sockaddr)
-		except OSError:
-			pass
-
-	def accept(self):
-		self.conn, addr = self.socket.accept()
-
-	def send(self, packet):
-		self.conn.send(packet)
-
-	def recv(self):
-		maxlen = 2048
-		packet = self.conn.recv(maxlen)
-		if len(packet) < 1:
-			return None
-		if len(packet) >= maxlen:
-			raise PacketTooLarge
-		return packet
-
-	def close(self):
-		if hasattr(self, "conn"):
-			self.conn.shutdown(socket.SHUT_RDWR)
-			self.conn.close()
-		if hasattr(self, "socket"):
-			self.socket.shutdown(socket.SHUT_RDWR)
-			self.socket.close()
-		os.system("openvpn --rmtun --dev tap0")
-		os.system("rm -f /dev/net/tap")
-		self._cleanup_file()
-
-# XXX proof of concept
-server = VerilatorServer()
-server.accept()
-print("Connection accepted")
-
-TUNSETIFF	= 0x400454ca
-IFF_TAP		= 0x0002
-IFF_NO_PI 	= 0x1000
-
-def read():
-	while True:
-		packet = server.recv()
-		if packet is not None:
-			if packet[0] == messages["UART"]:
-				c = bytes(chr(packet[1]).encode('utf-8'))
-				os.write(server.serial, c)
-			elif packet[0] == messages["ETHERNET"]:
-				tap = os.open("/dev/net/tun", os.O_RDWR)
-				fcntl.ioctl(tap, TUNSETIFF, struct.pack("16sH", b"tap0", IFF_TAP | IFF_NO_PI))
-				os.write(tap, packet[1+8:-4])
-				os.close(tap)
-			elif packet[0] == messages["ACK"]:
-				server.ack = True
-
-def write():
-	while True:
-		for c in list(os.read(server.serial, 100)):
-			packet = [messages["UART"], c]
-			server.send(bytes(packet))
-			while not server.ack:
-				pass
-			server.ack = False
-
-readthread = threading.Thread(target=read, daemon=True)
-readthread.start()
-
-writethread = threading.Thread(target=write, daemon=True)
-writethread.start()
-
-try:
-    while True:
-       time.sleep(1)
-except KeyboardInterrupt:
-	server.close()
-
diff --git a/mibuild/sim/server_tb.cpp b/mibuild/sim/server_tb.cpp
deleted file mode 100644
index 8563eebfd..000000000
--- a/mibuild/sim/server_tb.cpp
+++ /dev/null
@@ -1,236 +0,0 @@
-// This file is Copyright (c) 2015 Florent Kermarrec <florent@enjoy-digital.fr>
-// License: BSD
-
-#include <time.h>
-
-#include "Vdut.h"
-#include "verilated.h"
-#include "verilated_vcd_c.h"
-
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include <unistd.h>
-#include <sys/types.h>
-#include <sys/select.h>
-#include <sys/socket.h>
-#include <netinet/in.h>
-#include <sys/un.h>
-#include <netdb.h>
-#include <pthread.h>
-
-#define MAX(a,b) (((a)>(b))?(a):(b))
-#define MIN(a,b) (((a)<(b))?(a):(b))
-
-int trace = 0;
-
-vluint64_t main_time = 0;
-double sc_time_stamp()
-{
-	return main_time;
-}
-
-Vdut* dut;
-VerilatedVcdC* tfp;
-
-/* ios */
-
-#define MAX_LEN 2048
-
-enum {
-	MESSAGE_EXIT = 0,
-	MESSAGE_ACK,
-	MESSAGE_ERROR,
-	MESSAGE_UART,
-	MESSAGE_ETH
-};
-
-struct sim {
-	int socket;
-	bool run;
-
-	unsigned int tick;
-	clock_t start;
-	clock_t end;
-	float speed;
-
-	char txbuffer[MAX_LEN];
-	char rxbuffer[MAX_LEN];
-
-	char rx_serial_stb;
-	char rx_serial_data;
-	char rx_serial_presented;
-};
-
-unsigned char eth_txbuffer[1532];
-unsigned char eth_rxbuffer[1532];
-int eth_txbuffer_len = 0;
-int eth_rxbuffer_len = 0;
-int eth_rxbuffer_pos = 0;
-
-int sim_connect(struct sim *s, const char *sockaddr)
-{
-	struct sockaddr_un addr;
-
-	s->socket = socket(AF_UNIX, SOCK_SEQPACKET, 0);
-	if(s->socket < 0) {
-		return -1;
-	}
-
-	addr.sun_family = AF_UNIX;
-	strcpy(addr.sun_path, sockaddr);
-	if(connect(s->socket, (struct sockaddr *)&addr, sizeof(addr)) != 0) {
-		close(s->socket);
-		return -1;
-	}
-
-	return 0;
-}
-
-int sim_send(struct sim *s, char *buffer, int len)
-{
-	send(s->socket, s->txbuffer, len, 0);
-	return 0;
-}
-
-void sim_receive_process(struct sim *s, char * buffer, int len) {
-	int i;
-	switch(buffer[0]) {
-		case MESSAGE_EXIT:
-			s->run = false;
-			break;
-		case MESSAGE_UART:
-			i = 0;
-			for(i=0; i<len-1; i++) {
-				s->rx_serial_stb = 1;
-				s->rx_serial_data = buffer[i+1];
-				while (s->rx_serial_presented == 0);
-				s->rx_serial_presented = 0;
-			}
-			s->rx_serial_stb = 0;
-			break;
-		default:
-			break;
-	}
-}
-
-void *sim_receive(void *s_void)
-{
-	struct sim *s = (sim *) s_void;
-	int rxlen;
-	while(1)
-	{
-		rxlen = recv(s->socket, s->rxbuffer, MAX_LEN, 0);
-		if (rxlen > 0)
-			sim_receive_process(s, s->rxbuffer, rxlen);
-		s->txbuffer[0] = MESSAGE_ACK;
-		sim_send(s, s->txbuffer, 1);
-	}
-}
-
-void sim_destroy(struct sim *s)
-{
-	close(s->socket);
-	free(s);
-}
-
-int console_service(struct sim *s)
-{
-	/* fpga --> console */
-	SERIAL_SOURCE_ACK = 1;
-	if(SERIAL_SOURCE_STB == 1) {
-		s->txbuffer[0] = MESSAGE_UART;
-		s->txbuffer[1] = SERIAL_SOURCE_DATA;
-		sim_send(s, s->txbuffer, 2);
-	}
-
-	/* console --> fpga */
-	SERIAL_SINK_STB = s->rx_serial_stb;
-	SERIAL_SINK_DATA = s->rx_serial_data;
-	if (SERIAL_SINK_STB & SERIAL_SINK_ACK)
-		s->rx_serial_presented = s->rx_serial_stb;
-
-	return 0;
-}
-
-#ifdef ETH_SOURCE_STB
-int eth_last_source_stb = 0;
-
-int ethernet_service(struct sim *s) {
-	/* fpga --> ethernet tap */
-	ETH_SOURCE_ACK = 1;
-	if(ETH_SOURCE_STB == 1) {
-		eth_txbuffer[eth_txbuffer_len] = ETH_SOURCE_DATA;
-		eth_txbuffer_len++;
-	} else {
-		if (eth_last_source_stb) {
-			s->txbuffer[0] = MESSAGE_ETH;
-			memcpy(s->txbuffer+1, eth_txbuffer, eth_txbuffer_len);
-			sim_send(s, s->txbuffer, eth_txbuffer_len+1);
-			eth_txbuffer_len = 0;
-		}
-	}
-	eth_last_source_stb = ETH_SOURCE_STB;
-}
-#endif
-
-void sim_tick(struct sim *s)
-{
-	SYS_CLK = s->tick%2;
-	dut->eval();
-	if (trace)
-		tfp->dump(s->tick);
-	s->tick++;
-}
-
-void sim_init(struct sim *s)
-{
-	int i;
-	s->tick = 0;
-#ifdef SYS_RST
-	SYS_RST = 1;
-	SYS_CLK = 0;
-	for (i=0; i<8; i++)
-		sim_tick(s);
-	SYS_RST = 0;
-#endif
-	s->start = clock();
-}
-
-int main(int argc, char **argv, char **env)
-{
-	Verilated::commandArgs(argc, argv);
-	dut = new Vdut;
-
-	Verilated::traceEverOn(true);
-	tfp = new VerilatedVcdC;
-	dut->trace(tfp, 99);
-	tfp->open("dut.vcd");
-
-	struct sim s;
-	sim_init(&s);
-	sim_connect(&s, "/tmp/simsocket");
-
-	pthread_t sim_receive_thread;
-
-	pthread_create(&sim_receive_thread, NULL, sim_receive, &s);
-
-	s.run = true;
-	while(s.run) {
-		sim_tick(&s);
-		if (SYS_CLK) {
-			if (console_service(&s) != 0)
-				s.run = false;
-#ifdef ETH_SOURCE_STB
-			ethernet_service(&s);
-#endif
-		}
-	}
-	s.end = clock();
-
-	tfp->close();
-	pthread_cancel(sim_receive_thread);
-	sim_destroy(&s);
-
-	exit(0);
-}