diff --git a/32blit-pico/CMakeLists.txt b/32blit-pico/CMakeLists.txt
index a6b6965fa..6aaf8bf64 100644
--- a/32blit-pico/CMakeLists.txt
+++ b/32blit-pico/CMakeLists.txt
@@ -39,6 +39,7 @@ target_sources(BlitHalPico INTERFACE
     ${CMAKE_CURRENT_LIST_DIR}/led.cpp
     ${CMAKE_CURRENT_LIST_DIR}/main.cpp
     ${CMAKE_CURRENT_LIST_DIR}/storage.cpp
+    ${CMAKE_CURRENT_LIST_DIR}/multiplayer.cpp
     ${CMAKE_CURRENT_LIST_DIR}/st7789.cpp
     ${CMAKE_CURRENT_LIST_DIR}/usb_descriptors.c
 )
diff --git a/32blit-pico/main.cpp b/32blit-pico/main.cpp
index 867302419..32b2eb1b6 100644
--- a/32blit-pico/main.cpp
+++ b/32blit-pico/main.cpp
@@ -14,6 +14,7 @@
 #include "file.hpp"
 #include "input.hpp"
 #include "led.hpp"
+#include "multiplayer.hpp"
 #include "usb.hpp"
 
 #include "engine/api_private.hpp"
@@ -205,6 +206,7 @@ int main() {
     update_audio(now);
     update_led();
     update_usb();
+    update_multiplayer();
 
     if(ms_to_next_update > 1 && !display_render_needed())
       best_effort_wfe_or_timeout(make_timeout_time_ms(ms_to_next_update - 1));
diff --git a/32blit-pico/multiplayer.cpp b/32blit-pico/multiplayer.cpp
new file mode 100644
index 000000000..3def9e473
--- /dev/null
+++ b/32blit-pico/multiplayer.cpp
@@ -0,0 +1,110 @@
+#include <cstring>
+#include "multiplayer.hpp"
+
+#include "usb.hpp"
+
+#include "engine/api_private.hpp"
+
+static bool multiplayer_enabled = false;
+static bool peer_connected = false;
+
+static uint8_t cur_header[8];
+static int header_pos = 0;
+
+static uint16_t mp_buffer_len, mp_buffer_off;
+static uint8_t *mp_buffer = nullptr;
+
+void send_multiplayer_handshake(bool is_reply) {
+  uint8_t val = 0;
+  if(multiplayer_enabled)
+    val = is_reply ? 2 : 1;
+
+  uint8_t buf[]{'3', '2', 'B', 'L', 'M', 'L', 'T','I', val};
+  usb_cdc_write(buf, 9);
+  usb_cdc_flush_write();
+}
+
+void update_multiplayer() {
+  if(!usb_cdc_connected()) {
+    peer_connected = false;
+  }
+
+  while(usb_cdc_read_available()) {
+    // match header
+    if(header_pos < 8) {
+      usb_cdc_read(cur_header + header_pos, 1);
+
+      const char *expected = "32BL";
+      if(header_pos >= 4 || cur_header[header_pos] == expected[header_pos])
+        header_pos++;
+      else
+        header_pos = 0;
+    } else {
+
+      // get USER packet
+      if(mp_buffer) {
+        mp_buffer_off += usb_cdc_read(mp_buffer + mp_buffer_off, mp_buffer_len - mp_buffer_off);
+
+        if(mp_buffer_off == mp_buffer_len) {
+          if(blit::api.message_received)
+            blit::api.message_received(mp_buffer, mp_buffer_len);
+
+          delete[] mp_buffer;
+          mp_buffer = nullptr;
+          header_pos = 0;
+        }
+        continue;
+      }
+
+      // got header
+      if(memcmp(cur_header + 4, "MLTI", 4) == 0) {
+        // handshake packet
+        uint8_t b;
+        usb_cdc_read(&b, 1);
+        peer_connected = b != 0;
+
+        if(peer_connected)
+          send_multiplayer_handshake(true);
+
+        // done
+        header_pos = 0;
+      } else if(memcmp(cur_header + 4, "USER", 4) == 0) {
+        if(usb_cdc_read_available() < 2)
+          break;
+
+        usb_cdc_read((uint8_t *)&mp_buffer_len, 2);
+        mp_buffer_off = 0;
+        mp_buffer = new uint8_t[mp_buffer_len];
+
+      } else {
+        printf("got: %c%c%c%c%c%c%c%c\n", cur_header[0], cur_header[1], cur_header[2], cur_header[3], cur_header[4], cur_header[5], cur_header[6], cur_header[7]);
+        header_pos = 0;
+      }
+    }
+  }
+}
+
+bool is_multiplayer_connected() {
+  return multiplayer_enabled && peer_connected;
+}
+
+void set_multiplayer_enabled(bool enabled) {
+  multiplayer_enabled = enabled;
+
+  if(!enabled)
+    send_multiplayer_handshake();
+}
+
+void send_multiplayer_message(const uint8_t *data, uint16_t len) {
+  if(!peer_connected)
+    return;
+
+  uint8_t buf[]{'3', '2', 'B', 'L', 'U', 'S', 'E','R',
+    uint8_t(len & 0xFF), uint8_t(len >> 8)
+  };
+  usb_cdc_write(buf, 10);
+
+  usb_cdc_write((uint8_t *)data, len);
+
+  usb_cdc_flush_write();
+}
diff --git a/32blit-pico/multiplayer.hpp b/32blit-pico/multiplayer.hpp
new file mode 100644
index 000000000..af6639ef6
--- /dev/null
+++ b/32blit-pico/multiplayer.hpp
@@ -0,0 +1,9 @@
+#pragma once
+#include <cstdint>
+
+void update_multiplayer();
+void send_multiplayer_handshake(bool is_reply = false);
+
+bool is_multiplayer_connected();
+void set_multiplayer_enabled(bool enabled);
+void send_multiplayer_message(const uint8_t *data, uint16_t len);
diff --git a/32blit-pico/tusb_config.h b/32blit-pico/tusb_config.h
index 162717ffa..55d4f47a9 100644
--- a/32blit-pico/tusb_config.h
+++ b/32blit-pico/tusb_config.h
@@ -107,7 +107,7 @@
 #define CFG_TUH_ENUMERATION_BUFSIZE 256
 
 #define CFG_TUH_HUB                 0
-#define CFG_TUH_CDC                 0
+#define CFG_TUH_CDC                 1
 #ifdef INPUT_USB_HID
 #define CFG_TUH_HID                 4 // typical keyboard + mouse device can have 3-4 HID interfaces
 #else
diff --git a/32blit-pico/usb.hpp b/32blit-pico/usb.hpp
index 477897204..59e7016ef 100644
--- a/32blit-pico/usb.hpp
+++ b/32blit-pico/usb.hpp
@@ -7,7 +7,8 @@ void update_usb();
 
 void usb_debug(const char *message);
 
-// TODO: separate multiplayer from usb
-bool is_multiplayer_connected();
-void set_multiplayer_enabled(bool enabled);
-void send_multiplayer_message(const uint8_t *data, uint16_t len);
+bool usb_cdc_connected();
+uint16_t usb_cdc_read(uint8_t *data, uint16_t len);
+uint32_t usb_cdc_read_available();
+void usb_cdc_write(const uint8_t *data, uint16_t len);
+void usb_cdc_flush_write();
diff --git a/32blit-pico/usb_device.cpp b/32blit-pico/usb_device.cpp
index cc96ebbec..1df405c5d 100644
--- a/32blit-pico/usb_device.cpp
+++ b/32blit-pico/usb_device.cpp
@@ -1,15 +1,11 @@
 #include "usb.hpp"
 
-#include <cstring>
-
 #include "tusb.h"
 
 #include "config.h"
 #include "file.hpp"
 #include "storage.hpp"
 
-#include "engine/api_private.hpp"
-
 // msc
 static bool storage_ejected = false;
 
@@ -95,99 +91,12 @@ bool tud_msc_is_writable_cb(uint8_t lun) {
 }
 
 // cdc
-static bool multiplayer_enabled = false;
-static bool peer_connected = false;
-
-static char cur_header[8];
-static int header_pos = 0;
-
-static uint16_t mp_buffer_len, mp_buffer_off;
-static uint8_t *mp_buffer = nullptr;
-
-static void send_all(const void *buffer, uint32_t len) {
-  uint32_t done = tud_cdc_write(buffer, len);
-
-  while(done < len) {
-    tud_task();
-    if(!tud_ready())
-      break;
-
-    done += tud_cdc_write((const char *)buffer + done, len - done);
-  }
-}
-
-static void send_handshake(bool is_reply = false) {
-  uint8_t val = 0;
-  if(multiplayer_enabled)
-    val = is_reply ? 2 : 1;
-
-  uint8_t buf[]{'3', '2', 'B', 'L', 'M', 'L', 'T','I', val};
-  send_all(buf, 9);
-  tud_cdc_write_flush();
-}
-
 void init_usb() {
   tusb_init();
 }
 
 void update_usb() {
   tud_task();
-
-  if(!tud_ready()) { // tud_cdc_connected returns false with STM USB host
-    peer_connected = false;
-  }
-
-  while(tud_cdc_available()) {
-    // match header
-    if(header_pos < 8) {
-      cur_header[header_pos] = tud_cdc_read_char();
-
-      const char *expected = "32BL";
-      if(header_pos >= 4 || cur_header[header_pos] == expected[header_pos])
-        header_pos++;
-      else
-        header_pos = 0;
-    } else {
-
-      // get USER packet
-      if(mp_buffer) {
-        mp_buffer_off += tud_cdc_read(mp_buffer + mp_buffer_off, mp_buffer_len - mp_buffer_off);
-
-        if(mp_buffer_off == mp_buffer_len) {
-          if(blit::api.message_received)
-            blit::api.message_received(mp_buffer, mp_buffer_len);
-
-          delete[] mp_buffer;
-          mp_buffer = nullptr;
-          header_pos = 0;
-        }
-        continue;
-      }
-
-      // got header
-      if(memcmp(cur_header + 4, "MLTI", 4) == 0) {
-        // handshake packet
-        peer_connected = tud_cdc_read_char() != 0;
-
-        if(peer_connected)
-          send_handshake(true);
-
-        // done
-        header_pos = 0;
-      } else if(memcmp(cur_header + 4, "USER", 4) == 0) {
-        if(tud_cdc_available() < 2)
-          break;
-
-        tud_cdc_read(&mp_buffer_len, 2);
-        mp_buffer_off = 0;
-        mp_buffer = new uint8_t[mp_buffer_len];
-
-      } else {
-        printf("got: %c%c%c%c%c%c%c%c\n", cur_header[0], cur_header[1], cur_header[2], cur_header[3], cur_header[4], cur_header[5], cur_header[6], cur_header[7]);
-        header_pos = 0;
-      }
-    }
-  }
 }
 
 void usb_debug(const char *message) {
@@ -195,30 +104,34 @@ void usb_debug(const char *message) {
     return;
 
   auto len = strlen(message);
-  send_all(message, len);
+  usb_cdc_write((uint8_t *)message, len);
 }
 
-bool is_multiplayer_connected() {
-  return multiplayer_enabled && peer_connected;
+bool usb_cdc_connected() {
+  // tud_cdc_connected returns false with STM32 USB host
+  return tud_ready(); //tud_cdc_connected();
 }
 
-void set_multiplayer_enabled(bool enabled) {
-  multiplayer_enabled = enabled;
+uint16_t usb_cdc_read(uint8_t *data, uint16_t len) {
+  return tud_cdc_read(data, len);
+}
 
-  if(!enabled)
-    send_handshake();
+uint32_t usb_cdc_read_available() {
+  return tud_cdc_available();
 }
 
-void send_multiplayer_message(const uint8_t *data, uint16_t len) {
-  if(!peer_connected)
-    return;
+void usb_cdc_write(const uint8_t *data, uint16_t len) {
+  uint32_t done = tud_cdc_write(data, len);
 
-  uint8_t buf[]{'3', '2', 'B', 'L', 'U', 'S', 'E','R',
-    uint8_t(len & 0xFF), uint8_t(len >> 8)
-  };
-  send_all(buf, 10);
+  while(done < len) {
+    tud_task();
+    if(!tud_ready())
+      break;
 
-  send_all((uint8_t *)data, len);
+    done += tud_cdc_write(data + done, len - done);
+  }
+}
 
+void usb_cdc_flush_write() {
   tud_cdc_write_flush();
 }
diff --git a/32blit-pico/usb_host.cpp b/32blit-pico/usb_host.cpp
index 585d6d486..1d78b62bd 100644
--- a/32blit-pico/usb_host.cpp
+++ b/32blit-pico/usb_host.cpp
@@ -1,6 +1,6 @@
 #include "usb.hpp"
 
-#include <cstring>
+#include "multiplayer.hpp"
 
 #include "tusb.h"
 
@@ -159,26 +159,53 @@ void tuh_hid_report_received_cb(uint8_t dev_addr, uint8_t instance, uint8_t cons
 }
 #endif
 
+// cdc
+static uint8_t cdc_index = 0; // TODO: multiple devices?
+
+void tuh_cdc_mount_cb(uint8_t idx) {
+  cdc_index = idx;
+
+  send_multiplayer_handshake();
+}
+
 void init_usb() {
   tusb_init();
 }
 
 void update_usb() {
   tuh_task();
+
+  // TODO: resend multiplayer handshake
 }
 
 void usb_debug(const char *message) {
 
 }
 
-// multiplayer could be supported with USB host, but we'd need a hub
-// (host code is used for hid)
-bool is_multiplayer_connected() {
-  return false;
+bool usb_cdc_connected() {
+  return tuh_cdc_mounted(cdc_index);
+}
+
+uint16_t usb_cdc_read(uint8_t *data, uint16_t len) {
+  return tuh_cdc_read(cdc_index, data, len);
+}
+
+uint32_t usb_cdc_read_available() {
+  return tuh_cdc_read_available(cdc_index);
 }
 
-void set_multiplayer_enabled(bool enabled) {
+void usb_cdc_write(const uint8_t *data, uint16_t len) {
+  uint32_t done = tuh_cdc_write(cdc_index,data, len);
+
+  while(done < len) {
+    tuh_task();
+    if(!tuh_cdc_mounted(cdc_index))
+      break;
+
+    done += tuh_cdc_write(cdc_index, data + done, len - done);
+  }
 }
 
-void send_multiplayer_message(const uint8_t *data, uint16_t len) {
+void usb_cdc_flush_write() {
+  tuh_cdc_write_flush(cdc_index);
 }