diff --git a/common/boot_control_interface.h b/common/boot_control_interface.h
index 3906e2f..c93de5c 100644
--- a/common/boot_control_interface.h
+++ b/common/boot_control_interface.h
@@ -59,8 +59,18 @@
   // every slot. In order to access the dynamic partitions in the target slot,
   // GetDynamicPartitionControl()->PreparePartitionsForUpdate() must be called
   // (with |update| == true for the first time for a payload, and |false| for
-  // for the rest of the times) prior to calling this function. On success,
-  // returns true and stores the block device in |device|.
+  // for the rest of the times) prior to calling this function.
+  // The handling may be different based on whether the partition is included
+  // in the update payload. On success, returns true; and stores the block
+  // device in |device|, if the partition is dynamic in |is_dynamic|.
+  virtual bool GetPartitionDevice(const std::string& partition_name,
+                                  Slot slot,
+                                  bool not_in_payload,
+                                  std::string* device,
+                                  bool* is_dynamic) const = 0;
+
+  // Overload of the above function. We assume the partition is always included
+  // in the payload.
   virtual bool GetPartitionDevice(const std::string& partition_name,
                                   Slot slot,
                                   std::string* device) const = 0;
diff --git a/common/boot_control_stub.cc b/common/boot_control_stub.cc
index 2eb9211..907f670 100644
--- a/common/boot_control_stub.cc
+++ b/common/boot_control_stub.cc
@@ -35,6 +35,15 @@
   return 0;
 }
 
+bool BootControlStub::GetPartitionDevice(const std::string& partition_name,
+                                         BootControlInterface::Slot slot,
+                                         bool not_in_payload,
+                                         std::string* device,
+                                         bool* is_dynamic) const {
+  LOG(ERROR) << __FUNCTION__ << " should never be called.";
+  return false;
+}
+
 bool BootControlStub::GetPartitionDevice(const string& partition_name,
                                          Slot slot,
                                          string* device) const {
diff --git a/common/boot_control_stub.h b/common/boot_control_stub.h
index cc16190..a1bdb96 100644
--- a/common/boot_control_stub.h
+++ b/common/boot_control_stub.h
@@ -41,6 +41,11 @@
   unsigned int GetNumSlots() const override;
   BootControlInterface::Slot GetCurrentSlot() const override;
   bool GetPartitionDevice(const std::string& partition_name,
+                          Slot slot,
+                          bool not_in_payload,
+                          std::string* device,
+                          bool* is_dynamic) const override;
+  bool GetPartitionDevice(const std::string& partition_name,
                           BootControlInterface::Slot slot,
                           std::string* device) const override;
   bool IsSlotBootable(BootControlInterface::Slot slot) const override;
diff --git a/common/fake_boot_control.h b/common/fake_boot_control.h
index bd9d9ca..adbacd6 100644
--- a/common/fake_boot_control.h
+++ b/common/fake_boot_control.h
@@ -48,7 +48,9 @@
 
   bool GetPartitionDevice(const std::string& partition_name,
                           BootControlInterface::Slot slot,
-                          std::string* device) const override {
+                          bool not_in_payload,
+                          std::string* device,
+                          bool* is_dynamic) const override {
     if (slot >= num_slots_)
       return false;
     auto part_it = devices_[slot].find(partition_name);
@@ -58,6 +60,12 @@
     return true;
   }
 
+  bool GetPartitionDevice(const std::string& partition_name,
+                          BootControlInterface::Slot slot,
+                          std::string* device) const override {
+    return GetPartitionDevice(partition_name, slot, false, device, nullptr);
+  }
+
   bool IsSlotBootable(BootControlInterface::Slot slot) const override {
     return slot < num_slots_ && is_bootable_[slot];
   }