using proto enum for types

proto/firmware.proto

@@ -2,6 +2,14 @@ syntax = "proto2";
 
 import "nanopb.proto";
 
+
+enum UsbPackageType {
+  FIRMWARESTART = 3841;        // 0xF01
+  FIRMWAREPACKAGE = 3842;      // 0xF02
+  FIRMWAREDONE = 3843;         // 0xF03
+  FIRMWAREPACKAGEACK = 3844;   // 0xF04
+}
+
 message FirmwareStart {
   required string name = 1 [(nanopb).max_size = 32];
   required uint32 size = 2;