diff --git a/wifi/1.2/Android.bp b/wifi/1.2/Android.bp
index 100b36b..f41324e 100644
--- a/wifi/1.2/Android.bp
+++ b/wifi/1.2/Android.bp
@@ -10,6 +10,7 @@
         "types.hal",
         "IWifi.hal",
         "IWifiChip.hal",
+        "IWifiChipEventCallback.hal",
         "IWifiNanIface.hal",
         "IWifiNanIfaceEventCallback.hal",
     ],
diff --git a/wifi/1.2/IWifiChip.hal b/wifi/1.2/IWifiChip.hal
index 72cbf81..d336a33 100644
--- a/wifi/1.2/IWifiChip.hal
+++ b/wifi/1.2/IWifiChip.hal
@@ -16,7 +16,9 @@
 
 package android.hardware.wifi@1.2;
 
+import @1.0::WifiStatus;
 import @1.1::IWifiChip;
+import IWifiChipEventCallback;
 
 /**
  * Interface that represents a chip that must be configured as a single unit.
@@ -24,4 +26,18 @@
  * to perform operations like NAN, RTT, etc.
  */
 interface IWifiChip extends @1.1::IWifiChip {
+    /**
+     * Requests notifications of significant events on this chip. Multiple calls
+     * to this must register multiple callbacks each of which must receive all
+     * events.
+     *
+     * @param callback An instance of the |IWifiChipEventCallback| HIDL interface
+     *        object.
+     * @return status WifiStatus of the operation.
+     *         Possible status codes:
+     *         |WifiStatusCode.SUCCESS|,
+     *         |WifiStatusCode.ERROR_WIFI_CHIP_INVALID|
+     */
+    registerEventCallback_1_2(IWifiChipEventCallback callback)
+        generates (WifiStatus status);
 };
diff --git a/wifi/1.2/IWifiChipEventCallback.hal b/wifi/1.2/IWifiChipEventCallback.hal
new file mode 100644
index 0000000..5d2e7e9
--- /dev/null
+++ b/wifi/1.2/IWifiChipEventCallback.hal
@@ -0,0 +1,71 @@
+/*
+ * Copyright 2017 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.hardware.wifi@1.2;
+
+import @1.0::IWifiChipEventCallback;
+import @1.0::WifiBand;
+
+/**
+ * Wifi chip event callbacks.
+ */
+interface IWifiChipEventCallback extends @1.0::IWifiChipEventCallback {
+    /**
+     * Struct describing the state of each iface operating on the radio chain
+     * (hardware MAC) on the device.
+     */
+    struct IfaceInfo {
+        /** Name of the interface (For ex: "wlan0"). */
+        string name;
+        /** Wifi channel on which this interface is operating. */
+        uint32_t channel;
+    };
+
+    /**
+     * Struct describing the state of each hardware radio chain (hardware MAC)
+     * on the device.
+     */
+    struct RadioModeInfo {
+        /**
+         * Identifier for this radio chain. This is vendor dependent & used
+         * only for debugging purposes.
+         */
+        uint32_t radioId;
+        /**
+         * List of bands on which this radio chain is operating.
+         * Can be one of:
+         * a) WifiBand.BAND_24GHZ => 2.4Ghz.
+         * b) WifiBand.BAND_5GHZ => 5Ghz.
+         * c) WifiBand.BAND_24GHZ_5GHZ = 2.4Ghz + 5Ghz (Radio is time sharing
+         * across the 2 bands).
+         */
+        WifiBand bandInfo;
+        /** List of interfaces on this radio chain (hardware MAC). */
+        vec<IfaceInfo> ifaceInfos;
+    };
+
+    /**
+     * Asynchronous callback indicating a radio mode change.
+     * Radio mode change could be a result of:
+     * a) Bringing up concurrent interfaces (For ex: STA + AP).
+     * b) Change in operating band of one of the concurrent interfaces (For ex:
+     * STA connection moved from 2.4G to 5G)
+     *
+     * @param radioModeInfos List of RadioModeInfo structures for each
+     * radio chain (hardware MAC) on the device.
+     */
+    oneway onRadioModeChange(vec<RadioModeInfo> radioModeInfos);
+};
diff --git a/wifi/1.2/default/Android.mk b/wifi/1.2/default/Android.mk
index 8d0262b..978cf63 100644
--- a/wifi/1.2/default/Android.mk
+++ b/wifi/1.2/default/Android.mk
@@ -94,6 +94,7 @@
 LOCAL_MODULE := android.hardware.wifi@1.0-service-tests
 LOCAL_PROPRIETARY_MODULE := true
 LOCAL_SRC_FILES := \
+    tests/hidl_struct_util_unit_tests.cpp \
     tests/main.cpp \
     tests/mock_wifi_feature_flags.cpp \
     tests/mock_wifi_legacy_hal.cpp \
diff --git a/wifi/1.2/default/hidl_struct_util.cpp b/wifi/1.2/default/hidl_struct_util.cpp
index f87828c..b1c609e 100644
--- a/wifi/1.2/default/hidl_struct_util.cpp
+++ b/wifi/1.2/default/hidl_struct_util.cpp
@@ -266,6 +266,57 @@
     CHECK(false);
 }
 
+bool convertLegacyWifiMacInfoToHidl(
+    const legacy_hal::WifiMacInfo& legacy_mac_info,
+    IWifiChipEventCallback::RadioModeInfo* hidl_radio_mode_info) {
+    if (!hidl_radio_mode_info) {
+        return false;
+    }
+    *hidl_radio_mode_info = {};
+
+    hidl_radio_mode_info->radioId = legacy_mac_info.wlan_mac_id;
+    // Convert from bitmask of bands in the legacy HAL to enum value in
+    // the HIDL interface.
+    if (legacy_mac_info.mac_band & legacy_hal::WLAN_MAC_2_4_BAND &&
+        legacy_mac_info.mac_band & legacy_hal::WLAN_MAC_5_0_BAND) {
+        hidl_radio_mode_info->bandInfo = WifiBand::BAND_24GHZ_5GHZ;
+    } else if (legacy_mac_info.mac_band & legacy_hal::WLAN_MAC_2_4_BAND) {
+        hidl_radio_mode_info->bandInfo = WifiBand::BAND_24GHZ;
+    } else if (legacy_mac_info.mac_band & legacy_hal::WLAN_MAC_5_0_BAND) {
+        hidl_radio_mode_info->bandInfo = WifiBand::BAND_5GHZ;
+    } else {
+        hidl_radio_mode_info->bandInfo = WifiBand::BAND_UNSPECIFIED;
+    }
+    std::vector<IWifiChipEventCallback::IfaceInfo> iface_info_vec;
+    for (const auto& legacy_iface_info : legacy_mac_info.iface_infos) {
+        IWifiChipEventCallback::IfaceInfo iface_info;
+        iface_info.name = legacy_iface_info.name;
+        iface_info.channel = legacy_iface_info.channel;
+        iface_info_vec.push_back(iface_info);
+    }
+    hidl_radio_mode_info->ifaceInfos = iface_info_vec;
+    return true;
+}
+
+bool convertLegacyWifiMacInfosToHidl(
+    const std::vector<legacy_hal::WifiMacInfo>& legacy_mac_infos,
+    std::vector<IWifiChipEventCallback::RadioModeInfo>* hidl_radio_mode_infos) {
+    if (!hidl_radio_mode_infos) {
+        return false;
+    }
+    *hidl_radio_mode_infos = {};
+
+    for (const auto& legacy_mac_info : legacy_mac_infos) {
+        IWifiChipEventCallback::RadioModeInfo hidl_radio_mode_info;
+        if (!convertLegacyWifiMacInfoToHidl(legacy_mac_info,
+                                            &hidl_radio_mode_info)) {
+            return false;
+        }
+        hidl_radio_mode_infos->push_back(hidl_radio_mode_info);
+    }
+    return true;
+}
+
 bool convertLegacyFeaturesToHidlStaCapabilities(
     uint32_t legacy_feature_set, uint32_t legacy_logger_feature_set,
     uint32_t* hidl_caps) {
diff --git a/wifi/1.2/default/hidl_struct_util.h b/wifi/1.2/default/hidl_struct_util.h
index 1208afd..ce4bb81 100644
--- a/wifi/1.2/default/hidl_struct_util.h
+++ b/wifi/1.2/default/hidl_struct_util.h
@@ -22,6 +22,7 @@
 #include <android/hardware/wifi/1.0/IWifiChip.h>
 #include <android/hardware/wifi/1.0/types.h>
 #include <android/hardware/wifi/1.1/IWifiChip.h>
+#include <android/hardware/wifi/1.2/IWifiChipEventCallback.h>
 #include <android/hardware/wifi/1.2/types.h>
 
 #include "wifi_legacy_hal.h"
@@ -55,6 +56,9 @@
     WifiDebugHostWakeReasonStats* hidl_stats);
 legacy_hal::wifi_power_scenario convertHidlTxPowerScenarioToLegacy(
     V1_1::IWifiChip::TxPowerScenario hidl_scenario);
+bool convertLegacyWifiMacInfosToHidl(
+    const std::vector<legacy_hal::WifiMacInfo>& legacy_mac_infos,
+    std::vector<IWifiChipEventCallback::RadioModeInfo>* hidl_radio_mode_infos);
 
 // STA iface conversion methods.
 bool convertLegacyFeaturesToHidlStaCapabilities(
diff --git a/wifi/1.2/default/tests/hidl_struct_util_unit_tests.cpp b/wifi/1.2/default/tests/hidl_struct_util_unit_tests.cpp
new file mode 100644
index 0000000..1d6e9e4
--- /dev/null
+++ b/wifi/1.2/default/tests/hidl_struct_util_unit_tests.cpp
@@ -0,0 +1,129 @@
+/*
+ * Copyright (C) 2017, The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <android-base/logging.h>
+#include <android-base/macros.h>
+#include <gmock/gmock.h>
+
+#undef NAN
+#include "hidl_struct_util.h"
+
+using testing::Test;
+
+namespace {
+constexpr uint32_t kMacId1 = 1;
+constexpr uint32_t kMacId2 = 2;
+constexpr uint32_t kIfaceChannel1 = 3;
+constexpr uint32_t kIfaceChannel2 = 5;
+constexpr char kIfaceName1[] = "wlan0";
+constexpr char kIfaceName2[] = "wlan1";
+}  // namespace
+namespace android {
+namespace hardware {
+namespace wifi {
+namespace V1_2 {
+namespace implementation {
+using namespace android::hardware::wifi::V1_0;
+
+class HidlStructUtilTest : public Test {};
+
+TEST_F(HidlStructUtilTest, CanConvertLegacyWifiMacInfosToHidlWithOneMac) {
+    std::vector<legacy_hal::WifiMacInfo> legacy_mac_infos;
+    legacy_hal::WifiMacInfo legacy_mac_info1 = {
+        .wlan_mac_id = kMacId1,
+        .mac_band =
+            legacy_hal::WLAN_MAC_5_0_BAND | legacy_hal::WLAN_MAC_2_4_BAND};
+    legacy_hal::WifiIfaceInfo legacy_iface_info1 = {.name = kIfaceName1,
+                                                    .channel = kIfaceChannel1};
+    legacy_hal::WifiIfaceInfo legacy_iface_info2 = {.name = kIfaceName2,
+                                                    .channel = kIfaceChannel2};
+    legacy_mac_info1.iface_infos.push_back(legacy_iface_info1);
+    legacy_mac_info1.iface_infos.push_back(legacy_iface_info2);
+    legacy_mac_infos.push_back(legacy_mac_info1);
+
+    std::vector<IWifiChipEventCallback::RadioModeInfo> hidl_radio_mode_infos;
+    ASSERT_TRUE(hidl_struct_util::convertLegacyWifiMacInfosToHidl(
+        legacy_mac_infos, &hidl_radio_mode_infos));
+
+    ASSERT_EQ(1u, hidl_radio_mode_infos.size());
+    auto hidl_radio_mode_info1 = hidl_radio_mode_infos[0];
+    EXPECT_EQ(legacy_mac_info1.wlan_mac_id, hidl_radio_mode_info1.radioId);
+    EXPECT_EQ(WifiBand::BAND_24GHZ_5GHZ, hidl_radio_mode_info1.bandInfo);
+    ASSERT_EQ(2u, hidl_radio_mode_info1.ifaceInfos.size());
+    auto hidl_iface_info1 = hidl_radio_mode_info1.ifaceInfos[0];
+    EXPECT_EQ(legacy_iface_info1.name, hidl_iface_info1.name);
+    EXPECT_EQ(static_cast<uint32_t>(legacy_iface_info1.channel),
+              hidl_iface_info1.channel);
+    auto hidl_iface_info2 = hidl_radio_mode_info1.ifaceInfos[1];
+    EXPECT_EQ(legacy_iface_info2.name, hidl_iface_info2.name);
+    EXPECT_EQ(static_cast<uint32_t>(legacy_iface_info2.channel),
+              hidl_iface_info2.channel);
+}
+
+TEST_F(HidlStructUtilTest, CanConvertLegacyWifiMacInfosToHidlWithTwoMac) {
+    std::vector<legacy_hal::WifiMacInfo> legacy_mac_infos;
+    legacy_hal::WifiMacInfo legacy_mac_info1 = {
+        .wlan_mac_id = kMacId1, .mac_band = legacy_hal::WLAN_MAC_5_0_BAND};
+    legacy_hal::WifiIfaceInfo legacy_iface_info1 = {.name = kIfaceName1,
+                                                    .channel = kIfaceChannel1};
+    legacy_hal::WifiMacInfo legacy_mac_info2 = {
+        .wlan_mac_id = kMacId2, .mac_band = legacy_hal::WLAN_MAC_2_4_BAND};
+    legacy_hal::WifiIfaceInfo legacy_iface_info2 = {.name = kIfaceName2,
+                                                    .channel = kIfaceChannel2};
+    legacy_mac_info1.iface_infos.push_back(legacy_iface_info1);
+    legacy_mac_infos.push_back(legacy_mac_info1);
+    legacy_mac_info2.iface_infos.push_back(legacy_iface_info2);
+    legacy_mac_infos.push_back(legacy_mac_info2);
+
+    std::vector<IWifiChipEventCallback::RadioModeInfo> hidl_radio_mode_infos;
+    ASSERT_TRUE(hidl_struct_util::convertLegacyWifiMacInfosToHidl(
+        legacy_mac_infos, &hidl_radio_mode_infos));
+
+    ASSERT_EQ(2u, hidl_radio_mode_infos.size());
+
+    // Find mac info 1.
+    const auto hidl_radio_mode_info1 = std::find_if(
+        hidl_radio_mode_infos.begin(), hidl_radio_mode_infos.end(),
+        [&legacy_mac_info1](const IWifiChipEventCallback::RadioModeInfo& x) {
+            return x.radioId == legacy_mac_info1.wlan_mac_id;
+        });
+    ASSERT_NE(hidl_radio_mode_infos.end(), hidl_radio_mode_info1);
+    EXPECT_EQ(WifiBand::BAND_5GHZ, hidl_radio_mode_info1->bandInfo);
+    ASSERT_EQ(1u, hidl_radio_mode_info1->ifaceInfos.size());
+    auto hidl_iface_info1 = hidl_radio_mode_info1->ifaceInfos[0];
+    EXPECT_EQ(legacy_iface_info1.name, hidl_iface_info1.name);
+    EXPECT_EQ(static_cast<uint32_t>(legacy_iface_info1.channel),
+              hidl_iface_info1.channel);
+
+    // Find mac info 2.
+    const auto hidl_radio_mode_info2 = std::find_if(
+        hidl_radio_mode_infos.begin(), hidl_radio_mode_infos.end(),
+        [&legacy_mac_info2](const IWifiChipEventCallback::RadioModeInfo& x) {
+            return x.radioId == legacy_mac_info2.wlan_mac_id;
+        });
+    ASSERT_NE(hidl_radio_mode_infos.end(), hidl_radio_mode_info2);
+    EXPECT_EQ(WifiBand::BAND_24GHZ, hidl_radio_mode_info2->bandInfo);
+    ASSERT_EQ(1u, hidl_radio_mode_info2->ifaceInfos.size());
+    auto hidl_iface_info2 = hidl_radio_mode_info2->ifaceInfos[0];
+    EXPECT_EQ(legacy_iface_info2.name, hidl_iface_info2.name);
+    EXPECT_EQ(static_cast<uint32_t>(legacy_iface_info2.channel),
+              hidl_iface_info2.channel);
+}
+}  // namespace implementation
+}  // namespace V1_2
+}  // namespace wifi
+}  // namespace hardware
+}  // namespace android
diff --git a/wifi/1.2/default/wifi_chip.cpp b/wifi/1.2/default/wifi_chip.cpp
index bc3404a..38301e9 100644
--- a/wifi/1.2/default/wifi_chip.cpp
+++ b/wifi/1.2/default/wifi_chip.cpp
@@ -306,7 +306,7 @@
 }
 
 Return<void> WifiChip::registerEventCallback(
-    const sp<IWifiChipEventCallback>& event_callback,
+    const sp<V1_0::IWifiChipEventCallback>& event_callback,
     registerEventCallback_cb hidl_status_cb) {
     return validateAndCall(this, WifiStatusCode::ERROR_WIFI_CHIP_INVALID,
                            &WifiChip::registerEventCallbackInternal,
@@ -520,6 +520,14 @@
                            hidl_status_cb);
 }
 
+Return<void> WifiChip::registerEventCallback_1_2(
+    const sp<IWifiChipEventCallback>& event_callback,
+    registerEventCallback_cb hidl_status_cb) {
+    return validateAndCall(this, WifiStatusCode::ERROR_WIFI_CHIP_INVALID,
+                           &WifiChip::registerEventCallbackInternal_1_2,
+                           hidl_status_cb, event_callback);
+}
+
 Return<void> WifiChip::debug(const hidl_handle& handle,
                              const hidl_vec<hidl_string>&) {
     if (handle != nullptr && handle->numFds >= 1) {
@@ -556,11 +564,9 @@
 }
 
 WifiStatus WifiChip::registerEventCallbackInternal(
-    const sp<IWifiChipEventCallback>& event_callback) {
-    if (!event_cb_handler_.addCallback(event_callback)) {
-        return createWifiStatus(WifiStatusCode::ERROR_UNKNOWN);
-    }
-    return createWifiStatus(WifiStatusCode::SUCCESS);
+    const sp<V1_0::IWifiChipEventCallback>& /* event_callback */) {
+    // Deprecated support for this callback.
+    return createWifiStatus(WifiStatusCode::ERROR_NOT_SUPPORTED);
 }
 
 std::pair<WifiStatus, uint32_t> WifiChip::getCapabilitiesInternal() {
@@ -997,6 +1003,14 @@
     return createWifiStatusFromLegacyError(legacy_status);
 }
 
+WifiStatus WifiChip::registerEventCallbackInternal_1_2(
+    const sp<IWifiChipEventCallback>& event_callback) {
+    if (!event_cb_handler_.addCallback(event_callback)) {
+        return createWifiStatus(WifiStatusCode::ERROR_UNKNOWN);
+    }
+    return createWifiStatus(WifiStatusCode::SUCCESS);
+}
+
 WifiStatus WifiChip::handleChipConfiguration(
     /* NONNULL */ std::unique_lock<std::recursive_mutex>* lock,
     ChipModeId mode_id) {
@@ -1030,6 +1044,13 @@
                    << legacyErrorToString(legacy_status);
         return createWifiStatusFromLegacyError(legacy_status);
     }
+    // Every time the HAL is restarted, we need to register the
+    // radio mode change callback.
+    WifiStatus status = registerRadioModeChangeCallback();
+    if (status.code != WifiStatusCode::SUCCESS) {
+        // This probably is not a critical failure?
+        LOG(ERROR) << "Failed to register radio mode change callback";
+    }
     return createWifiStatus(WifiStatusCode::SUCCESS);
 }
 
@@ -1073,6 +1094,36 @@
     return createWifiStatusFromLegacyError(legacy_status);
 }
 
+WifiStatus WifiChip::registerRadioModeChangeCallback() {
+    android::wp<WifiChip> weak_ptr_this(this);
+    const auto& on_radio_mode_change_callback =
+        [weak_ptr_this](const std::vector<legacy_hal::WifiMacInfo>& mac_infos) {
+            const auto shared_ptr_this = weak_ptr_this.promote();
+            if (!shared_ptr_this.get() || !shared_ptr_this->isValid()) {
+                LOG(ERROR) << "Callback invoked on an invalid object";
+                return;
+            }
+            std::vector<IWifiChipEventCallback::RadioModeInfo>
+                hidl_radio_mode_infos;
+            if (!hidl_struct_util::convertLegacyWifiMacInfosToHidl(
+                    mac_infos, &hidl_radio_mode_infos)) {
+                LOG(ERROR) << "Error converting wifi mac info";
+                return;
+            }
+            for (const auto& callback : shared_ptr_this->getEventCallbacks()) {
+                if (!callback->onRadioModeChange(hidl_radio_mode_infos)
+                         .isOk()) {
+                    LOG(ERROR) << "Failed to invoke onRadioModeChange"
+                               << " callback on: " << toString(callback);
+                }
+            }
+        };
+    legacy_hal::wifi_error legacy_status =
+        legacy_hal_.lock()->registerRadioModeChangeCallbackHandler(
+            getWlan0IfaceName(), on_radio_mode_change_callback);
+    return createWifiStatusFromLegacyError(legacy_status);
+}
+
 void WifiChip::populateModes() {
     // The chip combination supported for current devices is fixed.
     // They can be one of the following based on device features:
diff --git a/wifi/1.2/default/wifi_chip.h b/wifi/1.2/default/wifi_chip.h
index 4ffa8da..24a5486 100644
--- a/wifi/1.2/default/wifi_chip.h
+++ b/wifi/1.2/default/wifi_chip.h
@@ -74,7 +74,7 @@
     // HIDL methods exposed.
     Return<void> getId(getId_cb hidl_status_cb) override;
     Return<void> registerEventCallback(
-        const sp<IWifiChipEventCallback>& event_callback,
+        const sp<V1_0::IWifiChipEventCallback>& event_callback,
         registerEventCallback_cb hidl_status_cb) override;
     Return<void> getCapabilities(getCapabilities_cb hidl_status_cb) override;
     Return<void> getAvailableModes(
@@ -138,6 +138,9 @@
         resetTxPowerScenario_cb hidl_status_cb) override;
     Return<void> debug(const hidl_handle& handle,
                        const hidl_vec<hidl_string>& options) override;
+    Return<void> registerEventCallback_1_2(
+        const sp<IWifiChipEventCallback>& event_callback,
+        registerEventCallback_1_2_cb hidl_status_cb) override;
 
    private:
     void invalidateAndRemoveAllIfaces();
@@ -145,7 +148,7 @@
     // Corresponding worker functions for the HIDL methods.
     std::pair<WifiStatus, ChipId> getIdInternal();
     WifiStatus registerEventCallbackInternal(
-        const sp<IWifiChipEventCallback>& event_callback);
+        const sp<V1_0::IWifiChipEventCallback>& event_callback);
     std::pair<WifiStatus, uint32_t> getCapabilitiesInternal();
     std::pair<WifiStatus, std::vector<ChipMode>> getAvailableModesInternal();
     WifiStatus configureChipInternal(
@@ -192,10 +195,13 @@
     WifiStatus enableDebugErrorAlertsInternal(bool enable);
     WifiStatus selectTxPowerScenarioInternal(TxPowerScenario scenario);
     WifiStatus resetTxPowerScenarioInternal();
+    WifiStatus registerEventCallbackInternal_1_2(
+        const sp<IWifiChipEventCallback>& event_callback);
 
     WifiStatus handleChipConfiguration(
         std::unique_lock<std::recursive_mutex>* lock, ChipModeId mode_id);
     WifiStatus registerDebugRingBufferCallback();
+    WifiStatus registerRadioModeChangeCallback();
 
     void populateModes();
     std::vector<IWifiChip::ChipIfaceCombination>
diff --git a/wifi/1.2/default/wifi_legacy_hal.cpp b/wifi/1.2/default/wifi_legacy_hal.cpp
index 9abe514..5f40d50 100644
--- a/wifi/1.2/default/wifi_legacy_hal.cpp
+++ b/wifi/1.2/default/wifi_legacy_hal.cpp
@@ -148,6 +148,17 @@
     }
 }
 
+// Callback to be invoked for radio mode change indication.
+std::function<void(wifi_request_id, uint32_t, wifi_mac_info*)>
+    on_radio_mode_change_internal_callback;
+void onAsyncRadioModeChange(wifi_request_id id, uint32_t num_macs,
+                            wifi_mac_info* mac_infos) {
+    const auto lock = hidl_sync_util::acquireGlobalLock();
+    if (on_radio_mode_change_internal_callback) {
+        on_radio_mode_change_internal_callback(id, num_macs, mac_infos);
+    }
+}
+
 // Callback to be invoked for rtt results results.
 std::function<void(wifi_request_id, unsigned num_results,
                    wifi_rtt_result* rtt_results[])>
@@ -937,6 +948,41 @@
         0, getIfaceHandle(iface_name));
 }
 
+wifi_error WifiLegacyHal::registerRadioModeChangeCallbackHandler(
+    const std::string& iface_name,
+    const on_radio_mode_change_callback& on_user_change_callback) {
+    if (on_radio_mode_change_internal_callback) {
+        return WIFI_ERROR_NOT_AVAILABLE;
+    }
+    on_radio_mode_change_internal_callback = [on_user_change_callback](
+                                                 wifi_request_id /* id */,
+                                                 uint32_t num_macs,
+                                                 wifi_mac_info* mac_infos_arr) {
+        if (num_macs > 0 && mac_infos_arr) {
+            std::vector<WifiMacInfo> mac_infos_vec;
+            for (uint32_t i = 0; i < num_macs; i++) {
+                WifiMacInfo mac_info;
+                mac_info.wlan_mac_id = mac_infos_arr[i].wlan_mac_id;
+                mac_info.mac_band = mac_infos_arr[i].mac_band;
+                for (int32_t j = 0; j < mac_infos_arr[i].num_iface; j++) {
+                    WifiIfaceInfo iface_info;
+                    iface_info.name = mac_infos_arr[i].iface_info[j].iface_name;
+                    iface_info.channel = mac_infos_arr[i].iface_info[j].channel;
+                    mac_info.iface_infos.push_back(iface_info);
+                }
+                mac_infos_vec.push_back(mac_info);
+            }
+            on_user_change_callback(mac_infos_vec);
+        }
+    };
+    wifi_error status = global_func_table_.wifi_set_radio_mode_change_handler(
+        0, getIfaceHandle(iface_name), {onAsyncRadioModeChange});
+    if (status != WIFI_SUCCESS) {
+        on_radio_mode_change_internal_callback = nullptr;
+    }
+    return status;
+}
+
 wifi_error WifiLegacyHal::startRttRangeRequest(
     const std::string& iface_name, wifi_request_id id,
     const std::vector<wifi_rtt_config>& rtt_configs,
@@ -1324,6 +1370,7 @@
     on_rssi_threshold_breached_internal_callback = nullptr;
     on_ring_buffer_data_internal_callback = nullptr;
     on_error_alert_internal_callback = nullptr;
+    on_radio_mode_change_internal_callback = nullptr;
     on_rtt_results_internal_callback = nullptr;
     on_nan_notify_response_user_callback = nullptr;
     on_nan_event_publish_terminated_user_callback = nullptr;
diff --git a/wifi/1.2/default/wifi_legacy_hal.h b/wifi/1.2/default/wifi_legacy_hal.h
index da88f6b..bd68bcd 100644
--- a/wifi/1.2/default/wifi_legacy_hal.h
+++ b/wifi/1.2/default/wifi_legacy_hal.h
@@ -132,6 +132,26 @@
 // Callback for alerts.
 using on_error_alert_callback =
     std::function<void(int32_t, const std::vector<uint8_t>&)>;
+
+// Struct for the mac info from the legacy HAL. This is a cleaner version
+// of the |wifi_mac_info| & |wifi_iface_info|.
+typedef struct {
+    std::string name;
+    wifi_channel channel;
+} WifiIfaceInfo;
+
+typedef struct {
+    uint32_t wlan_mac_id;
+    /* BIT MASK of BIT(WLAN_MAC*) as represented by wlan_mac_band */
+    uint32_t mac_band;
+    /* Represents the connected Wi-Fi interfaces associated with each MAC */
+    std::vector<WifiIfaceInfo> iface_infos;
+} WifiMacInfo;
+
+// Callback for radio mode change
+using on_radio_mode_change_callback =
+    std::function<void(const std::vector<WifiMacInfo>&)>;
+
 /**
  * Class that encapsulates all legacy HAL interactions.
  * This class manages the lifetime of the event loop thread used by legacy HAL.
@@ -253,6 +273,10 @@
         const on_error_alert_callback& on_alert_callback);
     wifi_error deregisterErrorAlertCallbackHandler(
         const std::string& iface_name);
+    // Radio mode functions.
+    wifi_error registerRadioModeChangeCallbackHandler(
+        const std::string& iface_name,
+        const on_radio_mode_change_callback& on_user_change_callback);
     // RTT functions.
     wifi_error startRttRangeRequest(
         const std::string& iface_name, wifi_request_id id,
diff --git a/wifi/1.2/default/wifi_legacy_hal_stubs.cpp b/wifi/1.2/default/wifi_legacy_hal_stubs.cpp
index 28972cb..2ee2aa2 100644
--- a/wifi/1.2/default/wifi_legacy_hal_stubs.cpp
+++ b/wifi/1.2/default/wifi_legacy_hal_stubs.cpp
@@ -134,6 +134,7 @@
     populateStubFor(&hal_fn->wifi_configure_roaming);
     populateStubFor(&hal_fn->wifi_select_tx_power_scenario);
     populateStubFor(&hal_fn->wifi_reset_tx_power_scenario);
+    populateStubFor(&hal_fn->wifi_set_radio_mode_change_handler);
     return true;
 }
 }  // namespace legacy_hal