diff --git a/mesh.proto b/mesh.proto
index 0fbb94c..f05ab10 100644
--- a/mesh.proto
+++ b/mesh.proto
@@ -9,6 +9,7 @@ import "config.proto";
 import "module_config.proto";
 import "portnums.proto";
 import "telemetry.proto";
+import "xmodem.proto";
 
 option java_outer_classname = "MeshProtos";
 option csharp_namespace = "Meshtastic.Protobufs";
@@ -1288,8 +1289,15 @@ message FromRadio {
      */
     Channel channel = 10;
 
-    /* Queue status info */
+    /*
+     * Queue status info
+     */
     QueueStatus queueStatus = 11;
+
+    /*
+     * File Transfer Chunk
+     */
+    XModem xmodemPacket = 12;
   }
 }
 
@@ -1328,6 +1336,12 @@ message ToRadio {
      * (Sending this message is optional for clients)
      */
     bool disconnect = 4;
+
+    /*
+     * File Transfer Chunk
+     */
+
+    XModem xmodemPacket = 5;
   }
 }
 
diff --git a/xmodem.options b/xmodem.options
new file mode 100644
index 0000000..3af6125
--- /dev/null
+++ b/xmodem.options
@@ -0,0 +1,6 @@
+# options for nanopb
+# https://jpa.kapsi.fi/nanopb/docs/reference.html#proto-file-options
+
+*XModem.buffer max_size:128
+*XModem.seq int_size:16
+*XModem.crc16 int_size:16
diff --git a/xmodem.proto b/xmodem.proto
new file mode 100644
index 0000000..9cf787b
--- /dev/null
+++ b/xmodem.proto
@@ -0,0 +1,26 @@
+syntax = "proto3";
+
+option java_package = "com.geeksville.mesh";
+option optimize_for = LITE_RUNTIME;
+option go_package = "github.com/meshtastic/go/generated";
+
+option java_outer_classname = "XmodemProtos";
+option csharp_namespace = "Meshtastic.Protobufs";
+
+message XModem {
+  enum Control {
+    NUL   = 0;
+    SOH   = 1;
+    STX   = 2;
+    EOT   = 4;
+    ACK   = 6;
+    NAK   = 21;
+    CAN   = 24;
+    CTRLZ = 26;
+  }
+
+  Control control = 1;
+  uint32 seq = 2;
+  uint32 crc16 = 3;
+  bytes buffer = 4;
+}
\ No newline at end of file