diff --git a/cmd/load/main.go b/cmd/load/main.go
index f0b7274..759cda7 100644
--- a/cmd/load/main.go
+++ b/cmd/load/main.go
@@ -65,6 +65,29 @@ func run(buildDir string) error {
 	fmt.Println("Rebooting...")
 	_ = picotool.Reboot()
 
+	time.Sleep(3 * time.Second)
+
+	dev, err = picoserial.FindDevice()
+	if err != nil {
+		return err
+	}
+	if dev != "" {
+		t, err := picoserial.Open(dev)
+		if err != nil {
+			return err
+		}
+		c := client.New(t, 2*time.Second)
+		info, err := c.Info()
+		c.Close()
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "warning: Info request failed: %v\n", err)
+		} else {
+			fmt.Printf("MAC: %02X:%02X:%02X:%02X:%02X:%02X\n",
+				info.MAC[0], info.MAC[1], info.MAC[2],
+				info.MAC[3], info.MAC[4], info.MAC[5])
+		}
+	}
+
 	fmt.Println("Done.")
 	return nil
 }
diff --git a/include/msgpackpp.h b/include/msgpackpp.h
index 78fa97f..6acafc1 100644
--- a/include/msgpackpp.h
+++ b/include/msgpackpp.h
@@ -1,5 +1,6 @@
 #pragma once
 #include <algorithm>
+#include <array>
 #include <cassert>
 #include <cstdint>
 #include <expected>
@@ -366,6 +367,9 @@ public:
 
   pack_result pack(const std::vector<uint8_t> &v) { return pack_bin(v); }
 
+  template <size_t N>
+  pack_result pack(const std::array<uint8_t, N> &v) { return pack_bin(v); }
+
   template <typename... Ts>
   pack_result pack(const std::tuple<Ts...> &t) {
     auto r = pack_array(sizeof...(Ts));
@@ -725,6 +729,15 @@ inline result<parser> unpack(const parser &p, std::string &out) {
   return p.next();
 }
 
+template <size_t N>
+result<parser> unpack(const parser &p, std::array<uint8_t, N> &out) {
+  auto v = p.get_binary_view();
+  if (!v) return std::unexpected(v.error());
+  if (v->size() != N) return std::unexpected(error_code::type_error);
+  std::copy(v->begin(), v->end(), out.begin());
+  return p.next();
+}
+
 inline result<parser> unpack(const parser &p, std::vector<uint8_t> &out) {
   auto v = p.get_binary_view();
   if (!v) return std::unexpected(v.error());
diff --git a/include/protocol.h b/include/protocol.h
index e9629ce..961ac35 100644
--- a/include/protocol.h
+++ b/include/protocol.h
@@ -1,4 +1,5 @@
 #pragma once
+#include <array>
 #include <cstdint>
 #include <string>
 #include <tuple>
@@ -16,6 +17,19 @@ struct RequestPICOBOOT {
     auto as_tuple() { return std::tie(); }
 };
 
+struct RequestInfo {
+    static constexpr int8_t ext_id = 4;
+    auto as_tuple() const { return std::tie(); }
+    auto as_tuple() { return std::tie(); }
+};
+
+struct ResponseInfo {
+    static constexpr int8_t ext_id = 5;
+    std::array<uint8_t, 6> mac;
+    auto as_tuple() const { return std::tie(mac); }
+    auto as_tuple() { return std::tie(mac); }
+};
+
 struct DeviceError {
     static constexpr int8_t ext_id = 3;
     uint32_t code;
diff --git a/lib/client/client.go b/lib/client/client.go
index 1ae4291..d31d7da 100644
--- a/lib/client/client.go
+++ b/lib/client/client.go
@@ -90,3 +90,7 @@ func (c *Client) PICOBOOT() error {
 	_, err := roundTrip[ResponsePICOBOOT](c, &RequestPICOBOOT{})
 	return err
 }
+
+func (c *Client) Info() (*ResponseInfo, error) {
+	return roundTrip[ResponseInfo](c, &RequestInfo{})
+}
diff --git a/lib/client/types.go b/lib/client/types.go
index e48ff7d..c3cb7fe 100644
--- a/lib/client/types.go
+++ b/lib/client/types.go
@@ -5,6 +5,11 @@ import "github.com/theater/picomap/lib/msgpack"
 type ResponsePICOBOOT struct{}
 type RequestPICOBOOT struct{}
 
+type RequestInfo struct{}
+type ResponseInfo struct {
+	MAC [6]byte
+}
+
 type DeviceError struct {
 	Code    uint32
 	Message string
@@ -25,4 +30,6 @@ func init() {
 	msgpack.RegisterExt(1, (*ResponsePICOBOOT)(nil))
 	msgpack.RegisterExt(2, (*RequestPICOBOOT)(nil))
 	msgpack.RegisterExt(3, (*DeviceError)(nil))
+	msgpack.RegisterExt(4, (*RequestInfo)(nil))
+	msgpack.RegisterExt(5, (*ResponseInfo)(nil))
 }
diff --git a/picomap.cpp b/picomap.cpp
index 7da9345..979262f 100644
--- a/picomap.cpp
+++ b/picomap.cpp
@@ -52,6 +52,12 @@ int main() {
             sleep_ms(100);
             reset_usb_boot(0, 1);
             break;
+        case RequestInfo::ext_id: {
+            ResponseInfo info;
+            getSHAR(info.mac.data());
+            send_bytes(encode_response(msg->message_id, info));
+            break;
+        }
         }
     }
 }