diff --git a/platforms/nuttx/src/px4/common/SerialImpl.cpp b/platforms/nuttx/src/px4/common/SerialImpl.cpp
index 904d6124b1..076cd74d4e 100644
--- a/platforms/nuttx/src/px4/common/SerialImpl.cpp
+++ b/platforms/nuttx/src/px4/common/SerialImpl.cpp
@@ -339,12 +339,15 @@ ssize_t SerialImpl::write(const void *buffer, size_t buffer_size)
 	}
 
 	int written = ::write(_serial_fd, buffer, buffer_size);
-	tcdrain(_serial_fd); // Wait until all output is transmitted
 
 	if (written < 0) {
-		PX4_ERR("%s write error %d", _port, written);
+		if (errno != EAGAIN) {
+			PX4_ERR("%s write error %d", _port, written);
+		}
 	}
 
+	::fsync(_serial_fd);
+
 	return written;
 }
 
diff --git a/platforms/posix/src/px4/common/SerialImpl.cpp b/platforms/posix/src/px4/common/SerialImpl.cpp
index 2298c38292..3afbfa9537 100644
--- a/platforms/posix/src/px4/common/SerialImpl.cpp
+++ b/platforms/posix/src/px4/common/SerialImpl.cpp
@@ -325,13 +325,15 @@ ssize_t SerialImpl::write(const void *buffer, size_t buffer_size)
 	}
 
 	int written = ::write(_serial_fd, buffer, buffer_size);
-	::fsync(_serial_fd);
 
 	if (written < 0) {
-		PX4_ERR("%s write error %d", _port, written);
-
+		if (errno != EAGAIN) {
+			PX4_ERR("%s write error %d", _port, written);
+		}
 	}
 
+	::fsync(_serial_fd);
+
 	return written;
 }