diff --git a/fixposition_driver_lib/src/fixposition_driver.cpp b/fixposition_driver_lib/src/fixposition_driver.cpp
index d837817..d3c1cc0 100644
--- a/fixposition_driver_lib/src/fixposition_driver.cpp
+++ b/fixposition_driver_lib/src/fixposition_driver.cpp
@@ -208,7 +208,7 @@ std::size_t FixpositionDriver::Read(uint8_t* buf, const std::size_t size, const
         if (serial_) {
             rv = recv(sensor_fd_, buf, size, MSG_DONTWAIT);
         } else {
-            rv = read(sensor_fd_, buf, sizeof(buf));
+            rv = read(sensor_fd_, buf, size);
         }
         // We have some data
         if (rv >= 0) {