diff --git a/src/arduino/Print.h b/src/arduino/Print.h
index f2cdb51..b87a336 100644
--- a/src/arduino/Print.h
+++ b/src/arduino/Print.h
@@ -57,6 +57,12 @@ class Print
     size_t write(const char *buffer, size_t size) {
       return write((const uint8_t *)buffer, size);
     }
+    // add availableForWrite to make compatible with Arduino Print.h
+    // default to zero, meaning "a single write may block"
+    // should be overriden by subclasses with buffering
+    virtual int availableForWrite() {
+      return 0;
+    }
 
     size_t print(const __FlashStringHelper *);
     size_t print(const String &);