diff --git a/keymaster/4.0/vts/functional/Android.bp b/keymaster/4.0/vts/functional/Android.bp
index 7244ae3..db50080 100644
--- a/keymaster/4.0/vts/functional/Android.bp
+++ b/keymaster/4.0/vts/functional/Android.bp
@@ -19,7 +19,6 @@
     defaults: ["VtsHalTargetTestDefaults"],
     srcs: [
         "HmacKeySharingTest.cpp",
-        "KeymasterHidlTest.cpp",
         "VerificationTokenTest.cpp",
         "keymaster_hidl_hal_test.cpp",
     ],
@@ -27,9 +26,25 @@
         "android.hardware.keymaster@4.0",
         "libcrypto_static",
         "libkeymaster4support",
+        "libkeymaster4vtstest",
     ],
     test_suites: [
         "general-tests",
         "vts-core",
     ],
 }
+
+cc_test_library {
+    name: "libkeymaster4vtstest",
+    defaults: ["VtsHalTargetTestDefaults"],
+    srcs: [
+        "KeymasterHidlTest.cpp",
+    ],
+    export_include_dirs: [
+        ".",
+    ],
+    static_libs: [
+        "android.hardware.keymaster@4.0",
+        "libkeymaster4support",
+    ],
+}
diff --git a/keymaster/4.0/vts/functional/KeymasterHidlTest.cpp b/keymaster/4.0/vts/functional/KeymasterHidlTest.cpp
index 2d2ba63..d0ad433 100644
--- a/keymaster/4.0/vts/functional/KeymasterHidlTest.cpp
+++ b/keymaster/4.0/vts/functional/KeymasterHidlTest.cpp
@@ -44,11 +44,9 @@
 
 using namespace std::literals::chrono_literals;
 
-void KeymasterHidlTest::InitializeKeymaster() {
-    std::string instance_name = GetParam();
-    keymaster_ = IKeymasterDevice::getService(GetParam());
-    ASSERT_NE(keymaster_, nullptr);
-
+void KeymasterHidlTest::InitializeKeymaster(sp<IKeymasterDevice> keymaster) {
+    ASSERT_NE(keymaster, nullptr);
+    keymaster_ = keymaster;
     ASSERT_TRUE(keymaster_
                         ->getHardwareInfo([&](SecurityLevel securityLevel, const hidl_string& name,
                                               const hidl_string& author) {
@@ -57,15 +55,15 @@
                             author_ = author;
                         })
                         .isOk());
-}
-
-void KeymasterHidlTest::SetUp() {
-    InitializeKeymaster();
 
     os_version_ = support::getOsVersion();
     os_patch_level_ = support::getOsPatchlevel();
 }
 
+void KeymasterHidlTest::SetUp() {
+    InitializeKeymaster(IKeymasterDevice::getService(GetParam()));
+}
+
 ErrorCode KeymasterHidlTest::GenerateKey(const AuthorizationSet& key_desc, HidlBuf* key_blob,
                                          KeyCharacteristics* key_characteristics) {
     EXPECT_NE(key_blob, nullptr) << "Key blob pointer must not be null.  Test bug";
diff --git a/keymaster/4.0/vts/functional/KeymasterHidlTest.h b/keymaster/4.0/vts/functional/KeymasterHidlTest.h
index 34a4473..f495516 100644
--- a/keymaster/4.0/vts/functional/KeymasterHidlTest.h
+++ b/keymaster/4.0/vts/functional/KeymasterHidlTest.h
@@ -38,12 +38,14 @@
 using ::std::string;
 
 class HidlBuf : public hidl_vec<uint8_t> {
-    typedef hidl_vec<uint8_t> super;
+    using super = hidl_vec<uint8_t>;
 
   public:
     HidlBuf() {}
     HidlBuf(const super& other) : super(other) {}
-    HidlBuf(super&& other) : super(std::move(other)) {}
+    HidlBuf(super&& other) : super(std::move(other)) { other = {}; }
+    HidlBuf(const HidlBuf& other) : super(other) {}
+    HidlBuf(HidlBuf&& other) : super(std::move(other)) { other = HidlBuf(); }
     explicit HidlBuf(const std::string& other) : HidlBuf() { *this = other; }
 
     HidlBuf& operator=(const super& other) {
@@ -53,6 +55,18 @@
 
     HidlBuf& operator=(super&& other) {
         super::operator=(std::move(other));
+        other = {};
+        return *this;
+    }
+
+    HidlBuf& operator=(const HidlBuf& other) {
+        super::operator=(other);
+        return *this;
+    }
+
+    HidlBuf& operator=(HidlBuf&& other) {
+        super::operator=(std::move(other));
+        other.super::operator=({});
         return *this;
     }
 
@@ -77,7 +91,7 @@
         AbortIfNeeded();
     }
 
-    void InitializeKeymaster();
+    void InitializeKeymaster(sp<IKeymasterDevice> keymaster);
     IKeymasterDevice& keymaster() { return *keymaster_; }
     uint32_t os_version() { return os_version_; }
     uint32_t os_patch_level() { return os_patch_level_; }
diff --git a/keymaster/4.0/vts/functional/keymaster_hidl_hal_test.cpp b/keymaster/4.0/vts/functional/keymaster_hidl_hal_test.cpp
index ace389b..6cbe4da 100644
--- a/keymaster/4.0/vts/functional/keymaster_hidl_hal_test.cpp
+++ b/keymaster/4.0/vts/functional/keymaster_hidl_hal_test.cpp
@@ -352,11 +352,11 @@
     EXPECT_EQ(ErrorCode::OK, error);
     if (error != ErrorCode::OK) return false;
 
-    EXPECT_TRUE(att_attestation_version == 3);
+    EXPECT_GE(att_attestation_version, 3U);
 
     expected_sw_enforced.push_back(TAG_ATTESTATION_APPLICATION_ID, HidlBuf(app_id));
 
-    EXPECT_EQ(att_keymaster_version, 4U);
+    EXPECT_GE(att_keymaster_version, 4U);
     EXPECT_EQ(security_level, att_keymaster_security_level);
     EXPECT_EQ(security_level, att_attestation_security_level);