diff --git a/src/background_tasks.py b/src/background_tasks.py
index cbb64b1..a816139 100644
--- a/src/background_tasks.py
+++ b/src/background_tasks.py
@@ -1,11 +1,7 @@
 import asyncio
 import utime
 
-from hello import broadcast_hello_udp
 from mem_stats import print_mem
-from wifi_sta import try_reconnect
-
-_UDP_HELLO_ATTEMPT = 0
 
 
 async def presets_loop(presets, wdt):
@@ -18,41 +14,4 @@ async def presets_loop(presets, wdt):
             if utime.ticks_diff(now, last_mem_log) >= 5000:
                 print_mem("runtime")
                 last_mem_log = now
-        # tick() does not await; yield so UDP hello and HTTP/WebSocket can run.
         await asyncio.sleep(0)
-
-
-async def udp_hello_loop_after_http_ready(sta_if, settings, wdt, runtime_state):
-    """UDP hello on cadence; if STA drops, one reconnect campaign per iteration."""
-    global _UDP_HELLO_ATTEMPT
-    await asyncio.sleep(1)
-    started_ms = utime.ticks_ms()
-    while True:
-        try:
-            wifi_ok = sta_if.isconnected()
-        except Exception:
-            wifi_ok = False
-        if not wifi_ok:
-            ssid = settings.get("ssid") or ""
-            if ssid:
-                try_reconnect(sta_if, ssid, settings.get("password") or "", wdt)
-            try:
-                wifi_ok = sta_if.isconnected()
-            except Exception:
-                wifi_ok = False
-        if wifi_ok and runtime_state.hello:
-            _UDP_HELLO_ATTEMPT += 1
-            print("UDP hello broadcast attempt", _UDP_HELLO_ATTEMPT)
-            try:
-                broadcast_hello_udp(
-                    sta_if,
-                    settings.get("name", ""),
-                    wait_reply=False,
-                    wdt=wdt,
-                    dual_destinations=True,
-                )
-            except Exception as ex:
-                print("UDP hello broadcast failed:", ex)
-        elapsed_ms = utime.ticks_diff(utime.ticks_ms(), started_ms)
-        interval_s = 10 if elapsed_ms < 120000 else 30
-        await asyncio.sleep(interval_s)
diff --git a/src/controller_messages.py b/src/controller_messages.py
index 8d0946f..0e19993 100644
--- a/src/controller_messages.py
+++ b/src/controller_messages.py
@@ -40,8 +40,8 @@ def _log_rx(payload) -> None:
         print("rx (logging failed)")
 
 
-def process_data(payload, settings, presets, controller_ip=None):
-    """Read one controller message; binary v1 envelope or JSON v1, then apply fields."""
+def process_data(payload, settings, presets, controller_ip=None, save=False):
+    """Read one controller message; binary v2 envelope or JSON v1, then apply fields."""
     _log_rx(payload)
     data = None
     if isinstance(payload, (bytes, bytearray)):
@@ -58,6 +58,8 @@ def process_data(payload, settings, presets, controller_ip=None):
             return
     if data.get("v", "") != "1":
         return
+    if save:
+        data["save"] = True
     if "device_config" in data:
         apply_device_config(data, settings, presets)
     if "b" in data:
diff --git a/src/device_groups.py b/src/device_groups.py
new file mode 100644
index 0000000..3f5a975
--- /dev/null
+++ b/src/device_groups.py
@@ -0,0 +1,16 @@
+"""In-memory group membership for GROUP_CMD filtering."""
+
+_groups = []
+
+
+def groups_replace(group_ids):
+    global _groups
+    _groups = [str(g) for g in group_ids]
+
+
+def in_group(group_id):
+    return str(group_id) in _groups
+
+
+def list_groups():
+    return list(_groups)
diff --git a/src/espnow_transport.py b/src/espnow_transport.py
new file mode 100644
index 0000000..297cbf8
--- /dev/null
+++ b/src/espnow_transport.py
@@ -0,0 +1,119 @@
+"""ESP-NOW receive loop and boot announce."""
+
+import asyncio
+
+import espnow
+import network
+
+import device_groups as dg
+from espnow_wire import (
+    BROADCAST_MAC,
+    MSG_ANNOUNCE,
+    MSG_CMD,
+    MSG_GROUP_CMD,
+    MSG_GROUPS,
+    cmd_envelope,
+    pack_announce,
+    parse_group_cmd,
+    parse_groups,
+    wire_msg_type,
+)
+from controller_messages import process_data
+
+_esp = None
+_groups_received = False
+
+
+def init_espnow(settings):
+    global _esp
+    ch = 6
+    try:
+        ch = int(settings.get("wifi_channel", 6))
+    except (TypeError, ValueError):
+        pass
+    ch = max(1, min(11, ch))
+    sta = network.WLAN(network.STA_IF)
+    sta.active(True)
+    sta.config(channel=ch)
+    _esp = espnow.ESPNow()
+    _esp.active(True)
+    try:
+        _esp.add_peer(BROADCAST_MAC)
+    except Exception:
+        pass
+    return _esp
+
+
+def send_boot_announce(settings):
+    if _esp is None:
+        return
+    pkt = pack_announce(
+        settings.get("name", "led"),
+        settings.get("num_leds", 1),
+        color_order=settings.get("color_order", "rgb"),
+        startup_mode=settings.get("startup_mode", "default"),
+        brightness=settings.get("brightness", 32),
+    )
+    try:
+        _esp.send(BROADCAST_MAC, pkt)
+        print("espnow announce", len(pkt), "B")
+    except Exception as e:
+        print("espnow announce failed:", e)
+
+
+def _handle_packet(pkt, settings, presets):
+    global _groups_received
+    mt = wire_msg_type(pkt)
+    if mt == MSG_GROUPS:
+        ids = parse_groups(pkt)
+        if ids is not None:
+            dg.groups_replace(ids)
+            _groups_received = True
+            print("groups", ids)
+        return
+    if mt == MSG_GROUP_CMD:
+        parsed = parse_group_cmd(pkt)
+        if parsed is None:
+            return
+        gid, env = parsed
+        if not dg.in_group(gid):
+            return
+        from espnow_wire import _envelope_size
+
+        need = _envelope_size(env)
+        save = len(env) > need and env[need] == 1
+        body = env[:need] if save else env
+        if body:
+            process_data(body, settings, presets, save=save)
+        return
+    if mt == MSG_CMD:
+        env, save = cmd_envelope(pkt)
+        if env:
+            process_data(env, settings, presets, save=save)
+        return
+    if mt == MSG_ANNOUNCE:
+        return
+
+
+async def espnow_receive_loop(settings, presets, wdt=None):
+    global _groups_received
+    while True:
+        if _esp is None:
+            await asyncio.sleep(0.1)
+            continue
+        host, msg = _esp.recv(0)
+        if not host:
+            if not _groups_received:
+                await asyncio.sleep(5)
+                send_boot_announce(settings)
+            else:
+                await asyncio.sleep(0.02)
+            if wdt:
+                wdt.feed()
+            continue
+        try:
+            _handle_packet(msg, settings, presets)
+        except Exception as e:
+            print("espnow rx error:", e)
+        if wdt:
+            wdt.feed()
diff --git a/src/espnow_wire.py b/src/espnow_wire.py
new file mode 100644
index 0000000..0d4cd70
--- /dev/null
+++ b/src/espnow_wire.py
@@ -0,0 +1,110 @@
+"""ESP-NOW wire format (MicroPython). See docs/espnow-binary-protocol.md in led-controller."""
+
+import struct
+
+WIRE_MAGIC = 0x4C
+MAX_ESPNOW_PAYLOAD = 250
+
+MSG_ANNOUNCE = 0x01
+MSG_GROUPS = 0x02
+MSG_CMD = 0x03
+MSG_GROUP_CMD = 0x04
+
+BROADCAST_MAC = b"\xff\xff\xff\xff\xff\xff"
+
+COLOR_ORDER_TO_ENUM = {
+    "rgb": 0,
+    "rbg": 1,
+    "grb": 2,
+    "gbr": 3,
+    "brg": 4,
+    "bgr": 5,
+}
+STARTUP_MODE_TO_ENUM = {"default": 0, "last": 1, "off": 2}
+
+
+def _pack_header(msg_type, body):
+    pkt = bytes([WIRE_MAGIC, msg_type]) + body
+    if len(pkt) > MAX_ESPNOW_PAYLOAD:
+        raise ValueError("packet too large")
+    return pkt
+
+
+def pack_announce(
+    name,
+    num_leds,
+    color_order="rgb",
+    startup_mode="default",
+    brightness=32,
+    device_type=0,
+):
+    name_b = name.encode("utf-8")
+    co = COLOR_ORDER_TO_ENUM.get(str(color_order).lower(), 0)
+    sm = STARTUP_MODE_TO_ENUM.get(str(startup_mode).lower(), 0)
+    body = (
+        bytes([len(name_b)])
+        + name_b
+        + struct.pack("<H", int(num_leds))
+        + bytes([co & 7, sm & 3, max(0, min(255, int(brightness))), device_type & 255])
+    )
+    return _pack_header(MSG_ANNOUNCE, body)
+
+
+def parse_groups(payload):
+    if len(payload) >= 2 and payload[0] == WIRE_MAGIC:
+        if payload[1] != MSG_GROUPS:
+            return None
+        body = payload[2:]
+    else:
+        body = payload
+    if not body:
+        return []
+    off = 0
+    count = body[off]
+    off += 1
+    out = []
+    for _ in range(count):
+        gl = body[off]
+        off += 1
+        out.append(body[off : off + gl].decode("utf-8"))
+        off += gl
+    return out
+
+
+def parse_group_cmd(payload):
+    if len(payload) < 2 or payload[0] != WIRE_MAGIC or payload[1] != MSG_GROUP_CMD:
+        return None
+    body = payload[2:]
+    gl = body[0]
+    gid = body[1 : 1 + gl].decode("utf-8")
+    env = body[1 + gl :]
+    return gid, env
+
+
+HEADER_LEN = 5
+
+
+def _envelope_size(env):
+    if len(env) < HEADER_LEN:
+        return len(env)
+    lp, ls, ld = env[2], env[3], env[4]
+    return HEADER_LEN + lp + ls + ld
+
+
+def cmd_envelope(payload):
+    if len(payload) < 2 or payload[0] != WIRE_MAGIC or payload[1] != MSG_CMD:
+        return None, False
+    env = payload[2:]
+    if not env:
+        return None, False
+    need = _envelope_size(env)
+    if need > len(env):
+        return None, False
+    save = len(env) > need and env[need] == 1
+    return env[:need], save
+
+
+def wire_msg_type(payload):
+    if len(payload) >= 2 and payload[0] == WIRE_MAGIC:
+        return payload[1]
+    return None
diff --git a/src/main.py b/src/main.py
index c934d13..269bb75 100644
--- a/src/main.py
+++ b/src/main.py
@@ -1,33 +1,24 @@
-import print_timestamp  # noqa: F401 — prefixes every print with [ticks_ms]
+import print_timestamp  # noqa: F401
 from settings import Settings
 import machine
-import utime
 import asyncio
-import json
 import gc
-from microdot import Microdot
-from microdot.websocket import WebSocketError, with_websocket
+import network
+import espnow
 from presets import Presets
-from controller_messages import apply_startup_pattern, process_data
-from runtime_state import RuntimeState
-from background_tasks import presets_loop, udp_hello_loop_after_http_ready
+from controller_messages import apply_startup_pattern
+from background_tasks import presets_loop
+from espnow_transport import espnow_receive_loop, init_espnow, send_boot_announce
 from mem_stats import print_mem
-from wifi_sta import boot_sta
-try:
-    import uos as os
-except ImportError:
-    import os
+import json
 
 wdt = machine.WDT(timeout=10000)
 wdt.feed()
 
 machine.freq(160000000)
 
-
 settings = Settings()
-
 gc.collect()
-sta_if = boot_sta(settings, wdt)
 
 presets = Presets(settings["led_pin"], settings["num_leds"])
 presets.load(settings)
@@ -37,130 +28,32 @@ gc.collect()
 
 apply_startup_pattern(settings, presets)
 
+sta_if = network.WLAN(network.STA_IF)
+sta_if.active(True)
+print(sta_if.ifconfig())
+print(sta_if.config("channel"))
 
-def _print_network_ips(controller_ip=None):
-    """Always log STA address and led-controller (WS client) address when known."""
-    try:
-        led_ip = sta_if.ifconfig()[0]
-    except Exception:
-        led_ip = "?"
-    ctrl = controller_ip if controller_ip else "(not connected)"
-    print("led-driver IP:", led_ip, "  led-controller IP:", ctrl)
-
-
-_print_network_ips()
-print_mem("startup")
-
-runtime_state = RuntimeState()
-
-app = Microdot()
-
-
-def _safe_pattern_filename(name):
-    if not isinstance(name, str):
-        return False
-    if not name.endswith(".py"):
-        return False
-    if "/" in name or "\\" in name or ".." in name:
-        return False
-    return True
-
-
-@app.route("/ws")
-@with_websocket
-async def ws_handler(request, ws):
-    runtime_state.ws_connected()
-    controller_ip = None
-    try:
-        client_addr = getattr(request, "client_addr", None)
-        if isinstance(client_addr, (tuple, list)) and client_addr:
-            controller_ip = client_addr[0]
-        elif isinstance(client_addr, str):
-            controller_ip = client_addr
-    except Exception:
-        controller_ip = None
-    _print_network_ips(controller_ip)
-    print_mem("ws connect")
-    try:
-        while True:
-            data = await ws.receive()
-            if not data:
-                break
-            process_data(data, settings, presets, controller_ip=controller_ip)
-    except WebSocketError as e:
-        print("WS client disconnected:", e)
-    except OSError as e:
-        print("WS client dropped (OSError):", e)
-    finally:
-        runtime_state.ws_disconnected()
-
-
-@app.post("/patterns/upload")
-async def upload_pattern(request):
-    """Receive one pattern file body from led-controller and reload patterns."""
-    raw_name = request.args.get("name")
-    reload_raw = request.args.get("reload", "1")
-    reload_patterns = str(reload_raw).strip().lower() not in ("0", "false", "no", "off")
-
-    if not isinstance(raw_name, str) or not raw_name.strip():
-        return json.dumps({"error": "name is required"}), 400, {
-            "Content-Type": "application/json"
-        }
-    body = request.body
-    if not isinstance(body, (bytes, bytearray)) or not body:
-        return json.dumps({"error": "code is required"}), 400, {
-            "Content-Type": "application/json"
-        }
-    try:
-        code = body.decode("utf-8")
-    except UnicodeError:
-        return json.dumps({"error": "body must be utf-8 text"}), 400, {
-            "Content-Type": "application/json"
-        }
-    if not code.strip():
-        return json.dumps({"error": "code is required"}), 400, {
-            "Content-Type": "application/json"
-        }
-
-    name = raw_name.strip()
-    if not name.endswith(".py"):
-        name += ".py"
-    if not _safe_pattern_filename(name) or name in ("__init__.py", "main.py"):
-        return json.dumps({"error": "invalid pattern filename"}), 400, {
-            "Content-Type": "application/json"
-        }
-
-    try:
-        os.mkdir("patterns")
-    except OSError:
-        pass
-
-    path = "patterns/" + name
-    try:
-        with open(path, "w") as f:
-            f.write(code)
-        if reload_patterns:
-            presets.reload_patterns()
-    except OSError as e:
-        print("patterns/upload failed:", e)
-        return json.dumps({"error": str(e)}), 500, {
-            "Content-Type": "application/json"
-        }
-
-    return json.dumps({
-        "message": "pattern uploaded",
-        "name": name,
-        "reloaded": reload_patterns,
-    }), 201, {"Content-Type": "application/json"}
-
-
-async def main(port=80):
-    asyncio.create_task(presets_loop(presets, wdt))
-    asyncio.create_task(
-        udp_hello_loop_after_http_ready(sta_if, settings, wdt, runtime_state)
-    )
-    await app.start_server(host="0.0.0.0", port=port)
+esp = espnow.ESPNow()
+esp.active(True)
+esp.add_peer(b"\xff\xff\xff\xff\xff\xff")
+
+hello = json.dumps({
+    "v": "1",
+    "settings": settings,
+    "type": "led",
+})
+esp.send(b"\xff\xff\xff\xff\xff\xff", hello)
+print(hello)
 
 
+async def main():
+    while True:
+        presets.tick()
+        wdt.feed()
+        if esp.any():
+            host, msg = esp.recv(0)
+            print(host, msg)
+        await asyncio.sleep(0)
+        
 if __name__ == "__main__":
-    asyncio.run(main(port=80))
+    asyncio.run(main())
diff --git a/src/settings.py b/src/settings.py
index 63ef712..3015259 100644
--- a/src/settings.py
+++ b/src/settings.py
@@ -31,11 +31,9 @@ class Settings(dict):
         # Power-on: "default" | "last" | "off"
         self["startup_mode"] = "default"
         self["brightness"] = 32
-        self["transport_type"] = "espnow"
+      
         self["wifi_channel"] = 1
-        # ESP-NOW transport (requires espnow firmware; uses wifi_channel).
-        self["ssid"] = ""
-        self["password"] = ""
+       
 
     def save(self):
         try: