diff --git a/src/processor/processor_imu.cpp b/src/processor/processor_imu.cpp
index fea5b04d63af0f827865bd646ec88150d5b1fae7..45ad4668701ae85aeeb46d84c7c8ae18873fb5ef 100644
--- a/src/processor/processor_imu.cpp
+++ b/src/processor/processor_imu.cpp
@@ -343,7 +343,7 @@ VectorXd ProcessorImu::bootstrapDelta() const
     }
     // now compose with delta in last_ptr_
     dt                = last_ptr_->getBuffer().back().ts_ - origin_ptr_->getTimeStamp();
-    const auto& delta = last_ptr_->getDeltaPreint();
+    const auto& delta = last_ptr_->getBuffer().back().delta_integr_;
     delta_int         = imu::compose(delta_int, delta, dt);
 
     return delta_int;