diff --git a/payload_consumer/filesystem_verifier_action.cc b/payload_consumer/filesystem_verifier_action.cc
index 36e5a35..b6affc3 100644
--- a/payload_consumer/filesystem_verifier_action.cc
+++ b/payload_consumer/filesystem_verifier_action.cc
@@ -76,9 +76,16 @@
     return;
   if (code == ErrorCode::kSuccess && HasOutputPipe())
     SetOutputObject(install_plan_);
+  UpdateProgress(1.0);
   processor_->ActionComplete(this, code);
 }
 
+void FilesystemVerifierAction::UpdateProgress(double progress) {
+  if (delegate_ != nullptr) {
+    delegate_->OnVerifyProgressUpdate(progress);
+  }
+}
+
 void FilesystemVerifierAction::StartPartitionHashing() {
   if (partition_index_ == install_plan_.partitions.size()) {
     Cleanup(ErrorCode::kSuccess);
@@ -187,7 +194,6 @@
     Cleanup(ErrorCode::kError);
     return;
   }
-
   if (bytes_read == 0) {
     LOG(ERROR) << "Failed to read the remaining " << partition_size_ - offset_
                << " bytes from partition "
@@ -202,6 +208,13 @@
     return;
   }
 
+  // WE don't consider sizes of each partition. Every partition
+  // has the same length on progress bar.
+  // TODO(zhangkelvin) Take sizes of each partition into account
+
+  UpdateProgress(
+      (static_cast<double>(offset_) / partition_size_ + partition_index_) /
+      install_plan_.partitions.size());
   if (verifier_step_ == VerifierStep::kVerifyTargetHash &&
       install_plan_.write_verity) {
     if (!verity_writer_->Update(offset_, buffer_.data(), bytes_read)) {
diff --git a/payload_consumer/filesystem_verifier_action.h b/payload_consumer/filesystem_verifier_action.h
index 83d6668..6ef3d16 100644
--- a/payload_consumer/filesystem_verifier_action.h
+++ b/payload_consumer/filesystem_verifier_action.h
@@ -49,6 +49,12 @@
   kVerifySourceHash,
 };
 
+class FilesystemVerifyDelegate {
+ public:
+  virtual ~FilesystemVerifyDelegate() = default;
+  virtual void OnVerifyProgressUpdate(double progress) = 0;
+};
+
 class FilesystemVerifierAction : public InstallPlanAction {
  public:
   FilesystemVerifierAction()
@@ -58,6 +64,14 @@
   void PerformAction() override;
   void TerminateProcessing() override;
 
+  // Used for listening to progress updates
+  void set_delegate(FilesystemVerifyDelegate* delegate) {
+    this->delegate_ = delegate;
+  }
+  [[nodiscard]] FilesystemVerifyDelegate* get_delegate() const {
+    return this->delegate_;
+  }
+
   // Debugging/logging
   static std::string StaticType() { return "FilesystemVerifierAction"; }
   std::string Type() const override { return StaticType(); }
@@ -85,6 +99,9 @@
   // true if TerminateProcessing() was called.
   void Cleanup(ErrorCode code);
 
+  // Invoke delegate callback to report progress, if delegate is not null
+  void UpdateProgress(double progress);
+
   // The type of the partition that we are verifying.
   VerifierStep verifier_step_ = VerifierStep::kVerifyTargetHash;
 
@@ -119,6 +136,9 @@
   // The byte offset that we are reading in the current partition.
   uint64_t offset_{0};
 
+  // An observer that observes progress updates of this action.
+  FilesystemVerifyDelegate* delegate_{};
+
   DISALLOW_COPY_AND_ASSIGN(FilesystemVerifierAction);
 };