Check buffer data and not buffer size

src/processor/processor_imu.cpp

@@ -265,7 +265,7 @@ void ProcessorImu::bootstrap()
         case ParamsProcessorImu::BootstrapMethod::BOOTSTRAP_G:
         {
             // Implementation of G strategy. 
-            if (last_ptr_->getBuffer().size() > params_motion_Imu_->bootstrap_averaging_length) 
+            if (last_ptr_->getBuffer().size() - 1 > params_motion_Imu_->bootstrap_averaging_length) 
             {
                 // frames:
                 //   w: world global ( where g = [0,0,-9.806] );