diff --git a/runtime/oat_file_assistant.cc b/runtime/oat_file_assistant.cc
index 4d1e1ea..6a62a16 100644
--- a/runtime/oat_file_assistant.cc
+++ b/runtime/oat_file_assistant.cc
@@ -314,7 +314,7 @@
   const OatFile::OatDexFile* oat_dex_file = file.GetOatDexFile(
       dex_location_.c_str(), dex_checksum_pointer, &error_msg);
   if (oat_dex_file == nullptr) {
-    VLOG(oat) << error_msg;
+    LOG(ERROR) << error_msg;
     return kOatDexOutOfDate;
   }
 
diff --git a/runtime/vdex_file.cc b/runtime/vdex_file.cc
index 843be92..dabf8c8 100644
--- a/runtime/vdex_file.cc
+++ b/runtime/vdex_file.cc
@@ -35,10 +35,12 @@
   return (memcmp(version_, kVdexVersion, sizeof(kVdexVersion)) == 0);
 }
 
-VdexFile::Header::Header(uint32_t dex_size,
+VdexFile::Header::Header(uint32_t number_of_dex_files,
+                         uint32_t dex_size,
                          uint32_t verifier_deps_size,
                          uint32_t quickening_info_size)
-    : dex_size_(dex_size),
+    : number_of_dex_files_(number_of_dex_files),
+      dex_size_(dex_size),
       verifier_deps_size_(verifier_deps_size),
       quickening_info_size_(quickening_info_size) {
   memcpy(magic_, kVdexMagic, sizeof(kVdexMagic));
diff --git a/runtime/vdex_file.h b/runtime/vdex_file.h
index 75a0d5e..3b114a9 100644
--- a/runtime/vdex_file.h
+++ b/runtime/vdex_file.h
@@ -43,7 +43,10 @@
  public:
   struct Header {
    public:
-    Header(uint32_t dex_size, uint32_t verifier_deps_size, uint32_t quickening_info_size);
+    Header(uint32_t number_of_dex_files_,
+           uint32_t dex_size,
+           uint32_t verifier_deps_size,
+           uint32_t quickening_info_size);
 
     const char* GetMagic() const { return reinterpret_cast<const char*>(magic_); }
     const char* GetVersion() const { return reinterpret_cast<const char*>(version_); }
@@ -54,18 +57,22 @@
     uint32_t GetDexSize() const { return dex_size_; }
     uint32_t GetVerifierDepsSize() const { return verifier_deps_size_; }
     uint32_t GetQuickeningInfoSize() const { return quickening_info_size_; }
+    uint32_t GetNumberOfDexFiles() const { return number_of_dex_files_; }
 
    private:
     static constexpr uint8_t kVdexMagic[] = { 'v', 'd', 'e', 'x' };
-    static constexpr uint8_t kVdexVersion[] = { '0', '0', '0', '\0' };
+    static constexpr uint8_t kVdexVersion[] = { '0', '0', '1', '\0' };
 
     uint8_t magic_[4];
     uint8_t version_[4];
+    uint32_t number_of_dex_files_;
     uint32_t dex_size_;
     uint32_t verifier_deps_size_;
     uint32_t quickening_info_size_;
   };
 
+  typedef uint32_t VdexChecksum;
+
   static VdexFile* Open(const std::string& vdex_filename,
                         bool writable,
                         bool low_4gb,
@@ -88,7 +95,7 @@
 
   ArrayRef<const uint8_t> GetVerifierDepsData() const {
     return ArrayRef<const uint8_t>(
-        Begin() + sizeof(Header) + GetHeader().GetDexSize(), GetHeader().GetVerifierDepsSize());
+        DexBegin() + GetHeader().GetDexSize(), GetHeader().GetVerifierDepsSize());
   }
 
   ArrayRef<const uint8_t> GetQuickeningInfo() const {
@@ -107,6 +114,12 @@
   // is none.
   const uint8_t* GetNextDexFileData(const uint8_t* cursor) const;
 
+  // Get the location checksum of the dex file number `dex_file_index`.
+  uint32_t GetLocationChecksum(uint32_t dex_file_index) const {
+    DCHECK_LT(dex_file_index, GetHeader().GetNumberOfDexFiles());
+    return reinterpret_cast<const uint32_t*>(Begin() + sizeof(Header))[dex_file_index];
+  }
+
  private:
   explicit VdexFile(MemMap* mmap) : mmap_(mmap) {}
 
@@ -115,11 +128,15 @@
   }
 
   const uint8_t* DexBegin() const {
-    return Begin() + sizeof(Header);
+    return Begin() + sizeof(Header) + GetSizeOfChecksumsSection();
   }
 
   const uint8_t* DexEnd() const {
-    return Begin() + sizeof(Header) + GetHeader().GetDexSize();
+    return DexBegin() + GetHeader().GetDexSize();
+  }
+
+  size_t GetSizeOfChecksumsSection() const {
+    return sizeof(VdexChecksum) * GetHeader().GetNumberOfDexFiles();
   }
 
   std::unique_ptr<MemMap> mmap_;