diff --git a/audio/effect/all-versions/default/Effect.cpp b/audio/effect/all-versions/default/Effect.cpp
index edd364c..58f1779 100644
--- a/audio/effect/all-versions/default/Effect.cpp
+++ b/audio/effect/all-versions/default/Effect.cpp
@@ -249,14 +249,17 @@
 
 void Effect::effectBufferConfigFromHal(const buffer_config_t& halConfig,
                                        EffectBufferConfig* config) {
-    config->buffer.id = 0;
-    config->buffer.frameCount = 0;
+    config->buffer.unspecified();
     audio_config_base_t halConfigBase = {halConfig.samplingRate,
                                          static_cast<audio_channel_mask_t>(halConfig.channels),
                                          static_cast<audio_format_t>(halConfig.format)};
-    (void)HidlUtils::audioConfigBaseFromHal(halConfigBase, mIsInput, &config->base);
-    config->accessMode = EffectBufferAccess(halConfig.accessMode);
-    config->mask = static_cast<decltype(config->mask)>(halConfig.mask);
+    (void)HidlUtils::audioConfigBaseOptionalFromHal(
+            halConfigBase, mIsInput, halConfig.mask & EFFECT_CONFIG_FORMAT,
+            halConfig.mask & EFFECT_CONFIG_SMP_RATE, halConfig.mask & EFFECT_CONFIG_CHANNELS,
+            &config->base);
+    if (halConfig.mask & EFFECT_CONFIG_ACC_MODE) {
+        config->accessMode.value(EffectBufferAccess(halConfig.accessMode));
+    }
 }
 
 // static
@@ -265,17 +268,32 @@
     // using 'setProcessBuffers'.
     halConfig->buffer.frameCount = 0;
     halConfig->buffer.raw = nullptr;
-    audio_config_base_t halConfigBase;
-    (void)HidlUtils::audioConfigBaseToHal(config.base, &halConfigBase);
-    halConfig->samplingRate = halConfigBase.sample_rate;
-    halConfig->channels = halConfigBase.channel_mask;
-    halConfig->format = halConfigBase.format;
+    audio_config_base_t halConfigBase = AUDIO_CONFIG_BASE_INITIALIZER;
+    bool formatSpecified = false, sRateSpecified = false, channelMaskSpecified = false;
+    (void)HidlUtils::audioConfigBaseOptionalToHal(config.base, &halConfigBase, &formatSpecified,
+                                                  &sRateSpecified, &channelMaskSpecified);
+    halConfig->mask = 0;
+    if (sRateSpecified) {
+        halConfig->mask |= EFFECT_CONFIG_SMP_RATE;
+        halConfig->samplingRate = halConfigBase.sample_rate;
+    }
+    if (channelMaskSpecified) {
+        halConfig->mask |= EFFECT_CONFIG_CHANNELS;
+        halConfig->channels = halConfigBase.channel_mask;
+    }
+    if (formatSpecified) {
+        halConfig->mask |= EFFECT_CONFIG_FORMAT;
+        halConfig->format = halConfigBase.format;
+    }
     // Note: The framework code does not use BP.
     halConfig->bufferProvider.cookie = nullptr;
     halConfig->bufferProvider.getBuffer = nullptr;
     halConfig->bufferProvider.releaseBuffer = nullptr;
-    halConfig->accessMode = static_cast<uint8_t>(config.accessMode);
-    halConfig->mask = static_cast<uint8_t>(config.mask);
+    if (config.accessMode.getDiscriminator() ==
+        EffectBufferConfig::OptionalAccessMode::hidl_discriminator::value) {
+        halConfig->mask |= EFFECT_CONFIG_ACC_MODE;
+        halConfig->accessMode = static_cast<uint8_t>(config.accessMode.value());
+    }
 }
 
 #endif  // MAJOR_VERSION <= 6
diff --git a/audio/effect/all-versions/vts/functional/VtsHalAudioEffectTargetTest.cpp b/audio/effect/all-versions/vts/functional/VtsHalAudioEffectTargetTest.cpp
index 35ff869..15a2fd9 100644
--- a/audio/effect/all-versions/vts/functional/VtsHalAudioEffectTargetTest.cpp
+++ b/audio/effect/all-versions/vts/functional/VtsHalAudioEffectTargetTest.cpp
@@ -264,8 +264,10 @@
     *channelCount = audio_channel_count_from_out_mask(
         static_cast<audio_channel_mask_t>(currentConfig.outputCfg.channels));
 #else
+    ASSERT_EQ(AudioConfigBaseOptional::ChannelMask::hidl_discriminator::value,
+              currentConfig.outputCfg.base.channelMask.getDiscriminator());
     *channelCount = android::audio::policy::configuration::V7_0::getChannelCount(
-            currentConfig.outputCfg.base.channelMask);
+            currentConfig.outputCfg.base.channelMask.value());
     ASSERT_NE(*channelCount, 0);
 #endif
 }
@@ -315,10 +317,10 @@
 std::vector<EffectBufferConfig> generateInvalidConfigs(const EffectBufferConfig& src) {
     std::vector<EffectBufferConfig> result;
     EffectBufferConfig invalidFormat = src;
-    invalidFormat.base.format = "random_string";
+    invalidFormat.base.format.value("random_string");
     result.push_back(std::move(invalidFormat));
     EffectBufferConfig invalidChannelMask = src;
-    invalidChannelMask.base.channelMask = "random_string";
+    invalidChannelMask.base.channelMask.value("random_string");
     result.push_back(std::move(invalidChannelMask));
     return result;
 }
@@ -395,17 +397,22 @@
            rhs.data.handle() == nullptr;
 }
 
+#if MAJOR_VERSION <= 6
 inline bool operator==(const EffectBufferConfig& lhs, const EffectBufferConfig& rhs) {
     return lhs.buffer == rhs.buffer &&
-#if MAJOR_VERSION <= 6
            lhs.samplingRateHz == rhs.samplingRateHz && lhs.channels == rhs.channels &&
            lhs.format == rhs.format &&
-#else
-           lhs.base.sampleRateHz == rhs.base.sampleRateHz &&
-           lhs.base.channelMask == rhs.base.channelMask && lhs.base.format == rhs.base.format &&
-#endif
            lhs.accessMode == rhs.accessMode && lhs.mask == rhs.mask;
 }
+#else
+inline bool operator==(const EffectBufferConfig& lhs, const EffectBufferConfig& rhs) {
+    return lhs.buffer.getDiscriminator() == rhs.buffer.getDiscriminator() &&
+           (lhs.buffer.getDiscriminator() ==
+                    EffectBufferConfig::OptionalBuffer::hidl_discriminator::unspecified ||
+            lhs.buffer.buf() == rhs.buffer.buf()) &&
+           lhs.base == rhs.base && lhs.accessMode == rhs.accessMode;
+}
+#endif  // MAJOR_VERSION <= 6
 
 inline bool operator==(const EffectConfig& lhs, const EffectConfig& rhs) {
     return lhs.inputCfg == rhs.inputCfg && lhs.outputCfg == rhs.outputCfg;