diff --git a/libwvdrmengine/cdm/core/src/cdm_engine.cpp b/libwvdrmengine/cdm/core/src/cdm_engine.cpp
index bcd11f21..74b9501a 100644
--- a/libwvdrmengine/cdm/core/src/cdm_engine.cpp
+++ b/libwvdrmengine/cdm/core/src/cdm_engine.cpp
@@ -1810,7 +1810,7 @@ CdmResponseType CdmEngine::ParseDecryptHashString(
     return INVALID_DECRYPT_HASH_FORMAT;
   }
 
-  std::vector<uint8_t> hash_vec = wvcdm::Base64Decode(tokens[2]);
+  std::vector<uint8_t> hash_vec = wvcdm::a2b_hex(tokens[2]);
   if (hash_vec.empty()) {
     LOGE("CdmEngine::ParseDecryptHashString: malformed hash: %s",
          hash_string.c_str());
diff --git a/libwvdrmengine/cdm/core/src/crypto_session.cpp b/libwvdrmengine/cdm/core/src/crypto_session.cpp
index 77bfa357..126bf590 100644
--- a/libwvdrmengine/cdm/core/src/crypto_session.cpp
+++ b/libwvdrmengine/cdm/core/src/crypto_session.cpp
@@ -1951,7 +1951,7 @@ CdmResponseType CryptoSession::GetDecryptHashError(std::string* error_string) {
   }
   error_string->clear();
 
-  uint32_t failed_frame_number;
+  uint32_t failed_frame_number = 0;
   OEMCryptoResult sts;
   WithOecSessionLock("GetDecryptHashError", [&] {
     sts = OEMCrypto_GetHashErrorCode(oec_session_id_, &failed_frame_number);
diff --git a/libwvdrmengine/cdm/core/test/cdm_engine_test.cpp b/libwvdrmengine/cdm/core/test/cdm_engine_test.cpp
index 08459042..87b09f5c 100644
--- a/libwvdrmengine/cdm/core/test/cdm_engine_test.cpp
+++ b/libwvdrmengine/cdm/core/test/cdm_engine_test.cpp
@@ -405,10 +405,10 @@ TEST_F(WvCdmEngineTest, ParseDecryptHashStringTest) {
   const std::string test_frame_number_string =
       std::to_string(test_frame_number);
   const std::string test_invalid_hash = "an invalid hash";
-  std::vector<uint8_t> binary_hash{ 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38 };
+  std::vector<uint8_t> binary_hash{ 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0xFF };
   const std::string test_valid_decoded_hash(binary_hash.begin(),
                                             binary_hash.end());
-  const std::string test_valid_hash = Base64Encode(binary_hash);
+  const std::string test_valid_hash = b2a_hex(binary_hash);
   const std::string test_invalid_hash_string = "sample hash string";
   const std::string test_valid_hash_string = test_session_id + kComma +
       test_frame_number_string + kComma + test_valid_hash;