diff --git a/radio/aidl/compat/libradiocompat/Android.bp b/radio/aidl/compat/libradiocompat/Android.bp
new file mode 100644
index 0000000..ada7c7e
--- /dev/null
+++ b/radio/aidl/compat/libradiocompat/Android.bp
@@ -0,0 +1,53 @@
+// Copyright (C) 2021 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 {
+    // See: http://go/android-license-faq
+    // A large-scale-change added 'default_applicable_licenses' to import
+    // all of the 'license_kinds' from "hardware_interfaces_license"
+    // to get the below license kinds:
+    //   SPDX-license-identifier-Apache-2.0
+    default_applicable_licenses: ["hardware_interfaces_license"],
+}
+
+cc_library {
+    name: "android.hardware.radio-library.compat",
+    relative_install_path: "hw",
+    vendor: true,
+    cflags: [
+        "-Wall",
+        "-Wextra",
+        //"-Wold-style-cast",  // TODO(b/203699028) enable after aosp/1900880 gets merged
+        "-DANDROID_UTILS_REF_BASE_DISABLE_IMPLICIT_CONSTRUCTION",
+    ],
+    shared_libs: [
+        "android.hardware.radio.config-V1-ndk",
+        "android.hardware.radio.config@1.0",
+        "android.hardware.radio.config@1.1",
+        "android.hardware.radio.config@1.2",
+        "android.hardware.radio.config@1.3",
+        "libbase",
+        "libbinder_ndk",
+        "libhidlbase",
+        "libutils",
+    ],
+    srcs: [
+        "commonStructs.cpp",
+        "config/RadioConfig.cpp",
+        "config/RadioConfigIndication.cpp",
+        "config/RadioConfigResponse.cpp",
+        "config/structs.cpp",
+    ],
+    export_include_dirs: ["include"],
+}
diff --git a/radio/aidl/compat/libradiocompat/collections.h b/radio/aidl/compat/libradiocompat/collections.h
new file mode 100644
index 0000000..9ef1351
--- /dev/null
+++ b/radio/aidl/compat/libradiocompat/collections.h
@@ -0,0 +1,54 @@
+/*
+ * Copyright (C) 2021 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.
+ */
+#pragma once
+
+#include <hidl/HidlSupport.h>
+
+namespace android::hardware::radio::compat {
+
+/**
+ * Converts hidl_vec<T> HIDL list to std::vector<T> AIDL list.
+ *
+ * To convert values, the template uses toAidl functions for a given type T, assuming it's defined.
+ *
+ * \param inp vector to convert
+ */
+template <typename T>
+auto toAidl(const hidl_vec<T>& inp) {
+    std::vector<decltype(toAidl(T{}))> out(inp.size());
+    for (size_t i = 0; i < inp.size(); i++) {
+        out[i] = toAidl(inp[i]);
+    }
+    return out;
+}
+
+/**
+ * Converts std::vector<T> AIDL list to hidl_vec<T> HIDL list.
+ *
+ * To convert values, the template uses toHidl functions for a given type T, assuming it's defined.
+ *
+ * \param inp vector to convert
+ */
+template <typename T>
+auto toHidl(const std::vector<T>& inp) {
+    hidl_vec<decltype(toHidl(T{}))> out(inp.size());
+    for (size_t i = 0; i < inp.size(); i++) {
+        out[i] = toHidl(inp[i]);
+    }
+    return out;
+}
+
+}  // namespace android::hardware::radio::compat
diff --git a/radio/aidl/compat/libradiocompat/commonStructs.cpp b/radio/aidl/compat/libradiocompat/commonStructs.cpp
new file mode 100644
index 0000000..e81562a
--- /dev/null
+++ b/radio/aidl/compat/libradiocompat/commonStructs.cpp
@@ -0,0 +1,63 @@
+/*
+ * Copyright (C) 2021 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 "commonStructs.h"
+
+namespace android::hardware::radio::compat {
+
+namespace aidl = ::aidl::android::hardware::radio;
+
+V1_6::RadioResponseInfo notSupported(int32_t serial) {
+    return {
+            .type = V1_0::RadioResponseType::SOLICITED,
+            .serial = serial,
+            .error = V1_6::RadioError::REQUEST_NOT_SUPPORTED,
+    };
+}
+
+aidl::RadioIndicationType toAidl(V1_0::RadioIndicationType type) {
+    return aidl::RadioIndicationType(type);
+}
+
+aidl::RadioResponseType toAidl(V1_0::RadioResponseType type) {
+    return aidl::RadioResponseType(type);
+}
+
+aidl::RadioError toAidl(V1_0::RadioError err) {
+    return aidl::RadioError(err);
+}
+
+aidl::RadioError toAidl(V1_6::RadioError err) {
+    return aidl::RadioError(err);
+}
+
+aidl::RadioResponseInfo toAidl(const V1_0::RadioResponseInfo& info) {
+    return {
+            .type = toAidl(info.type),
+            .serial = info.serial,
+            .error = toAidl(info.error),
+    };
+}
+
+aidl::RadioResponseInfo toAidl(const V1_6::RadioResponseInfo& info) {
+    return {
+            .type = toAidl(info.type),
+            .serial = info.serial,
+            .error = toAidl(info.error),
+    };
+}
+
+}  // namespace android::hardware::radio::compat
diff --git a/radio/aidl/compat/libradiocompat/commonStructs.h b/radio/aidl/compat/libradiocompat/commonStructs.h
new file mode 100644
index 0000000..cba307e
--- /dev/null
+++ b/radio/aidl/compat/libradiocompat/commonStructs.h
@@ -0,0 +1,34 @@
+/*
+ * Copyright (C) 2021 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.
+ */
+#pragma once
+
+#include <aidl/android/hardware/radio/RadioIndicationType.h>
+#include <aidl/android/hardware/radio/RadioResponseInfo.h>
+#include <android/hardware/radio/1.6/types.h>
+
+namespace android::hardware::radio::compat {
+
+V1_6::RadioResponseInfo notSupported(int32_t serial);
+
+aidl::android::hardware::radio::RadioIndicationType toAidl(V1_0::RadioIndicationType type);
+aidl::android::hardware::radio::RadioResponseType toAidl(V1_0::RadioResponseType type);
+aidl::android::hardware::radio::RadioError toAidl(V1_0::RadioError type);
+aidl::android::hardware::radio::RadioError toAidl(V1_6::RadioError type);
+
+aidl::android::hardware::radio::RadioResponseInfo toAidl(const V1_0::RadioResponseInfo& info);
+aidl::android::hardware::radio::RadioResponseInfo toAidl(const V1_6::RadioResponseInfo& info);
+
+}  // namespace android::hardware::radio::compat
diff --git a/radio/aidl/compat/libradiocompat/config/RadioConfig.cpp b/radio/aidl/compat/libradiocompat/config/RadioConfig.cpp
new file mode 100644
index 0000000..d0d6f7a
--- /dev/null
+++ b/radio/aidl/compat/libradiocompat/config/RadioConfig.cpp
@@ -0,0 +1,103 @@
+/*
+ * Copyright (C) 2021 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 <libradiocompat/RadioConfig.h>
+
+#include "RadioConfigIndication.h"
+#include "RadioConfigResponse.h"
+#include "commonStructs.h"
+#include "debug.h"
+#include "structs.h"
+
+#define RADIO_MODULE "Config"
+
+namespace android::hardware::radio::compat {
+
+using ::ndk::ScopedAStatus;
+namespace aidl = ::aidl::android::hardware::radio::config;
+constexpr auto ok = &ScopedAStatus::ok;
+
+RadioConfig::RadioConfig(sp<config::V1_1::IRadioConfig> hidlHal)
+    : mHal1_1(hidlHal), mHal1_3(config::V1_3::IRadioConfig::castFrom(hidlHal)) {}
+
+config::V1_3::IRadioConfigResponse& RadioConfig::respond() {
+    CHECK(mRadioConfigResponse) << "setResponseFunctions was not called yet";
+    return *mRadioConfigResponse;
+}
+
+ScopedAStatus RadioConfig::getHalDeviceCapabilities(int32_t serial) {
+    LOG_CALL << serial;
+    if (mHal1_3) {
+        mHal1_3->getHalDeviceCapabilities(serial);
+    } else {
+        respond().getHalDeviceCapabilitiesResponse(notSupported(serial), false);
+    }
+    return ok();
+}
+
+ScopedAStatus RadioConfig::getNumOfLiveModems(int32_t serial) {
+    LOG_CALL << serial;
+    mHal1_1->getModemsConfig(serial);
+    return ok();
+}
+
+ScopedAStatus RadioConfig::getPhoneCapability(int32_t serial) {
+    LOG_CALL << serial;
+    mHal1_1->getPhoneCapability(serial);
+    return ok();
+}
+
+ScopedAStatus RadioConfig::getSimSlotsStatus(int32_t serial) {
+    LOG_CALL << serial;
+    mHal1_1->getSimSlotsStatus(serial);
+    return ok();
+}
+
+ScopedAStatus RadioConfig::setNumOfLiveModems(int32_t serial, int8_t numOfLiveModems) {
+    LOG_CALL << serial;
+    mHal1_1->setModemsConfig(serial, {static_cast<uint8_t>(numOfLiveModems)});
+    return ok();
+}
+
+ScopedAStatus RadioConfig::setPreferredDataModem(int32_t serial, int8_t modemId) {
+    LOG_CALL << serial;
+    mHal1_1->setPreferredDataModem(serial, modemId);
+    return ok();
+}
+
+ScopedAStatus RadioConfig::setResponseFunctions(
+        const std::shared_ptr<aidl::IRadioConfigResponse>& radioConfigResponse,
+        const std::shared_ptr<aidl::IRadioConfigIndication>& radioConfigIndication) {
+    LOG_CALL << radioConfigResponse << ' ' << radioConfigIndication;
+
+    CHECK(radioConfigResponse);
+    CHECK(radioConfigIndication);
+
+    mRadioConfigResponse = sp<RadioConfigResponse>::make(radioConfigResponse);
+    mRadioConfigIndication = sp<RadioConfigIndication>::make(radioConfigIndication);
+    mHal1_1->setResponseFunctions(mRadioConfigResponse, mRadioConfigIndication);
+
+    return ok();
+}
+
+ScopedAStatus RadioConfig::setSimSlotsMapping(  //
+        int32_t serial, const std::vector<aidl::SlotPortMapping>& slotMap) {
+    LOG_CALL << serial;
+    mHal1_1->setSimSlotsMapping(serial, toHidl(slotMap));
+    return ok();
+}
+
+}  // namespace android::hardware::radio::compat
diff --git a/radio/aidl/compat/libradiocompat/config/RadioConfigIndication.cpp b/radio/aidl/compat/libradiocompat/config/RadioConfigIndication.cpp
new file mode 100644
index 0000000..0320ad7
--- /dev/null
+++ b/radio/aidl/compat/libradiocompat/config/RadioConfigIndication.cpp
@@ -0,0 +1,48 @@
+/*
+ * Copyright (C) 2021 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 "RadioConfigIndication.h"
+
+#include "commonStructs.h"
+#include "debug.h"
+#include "structs.h"
+
+#include "collections.h"
+
+#define RADIO_MODULE "ConfigIndication"
+
+namespace android::hardware::radio::compat {
+
+namespace aidl = ::aidl::android::hardware::radio::config;
+
+RadioConfigIndication::RadioConfigIndication(std::shared_ptr<aidl::IRadioConfigIndication> callback)
+    : mCallback(callback) {}
+
+Return<void> RadioConfigIndication::simSlotsStatusChanged(
+        V1_0::RadioIndicationType type, const hidl_vec<config::V1_0::SimSlotStatus>& slotStatus) {
+    LOG_CALL << type;
+    mCallback->simSlotsStatusChanged(toAidl(type), toAidl(slotStatus));
+    return {};
+}
+
+Return<void> RadioConfigIndication::simSlotsStatusChanged_1_2(
+        V1_0::RadioIndicationType type, const hidl_vec<config::V1_2::SimSlotStatus>& slotStatus) {
+    LOG_CALL << type;
+    mCallback->simSlotsStatusChanged(toAidl(type), toAidl(slotStatus));
+    return {};
+}
+
+}  // namespace android::hardware::radio::compat
diff --git a/radio/aidl/compat/libradiocompat/config/RadioConfigIndication.h b/radio/aidl/compat/libradiocompat/config/RadioConfigIndication.h
new file mode 100644
index 0000000..3d8d971
--- /dev/null
+++ b/radio/aidl/compat/libradiocompat/config/RadioConfigIndication.h
@@ -0,0 +1,38 @@
+/*
+ * Copyright (C) 2021 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.
+ */
+#pragma once
+
+#include <aidl/android/hardware/radio/config/IRadioConfigIndication.h>
+#include <android/hardware/radio/config/1.2/IRadioConfigIndication.h>
+
+namespace android::hardware::radio::compat {
+
+class RadioConfigIndication : public config::V1_2::IRadioConfigIndication {
+    std::shared_ptr<aidl::android::hardware::radio::config::IRadioConfigIndication> mCallback;
+
+    Return<void> simSlotsStatusChanged(
+            V1_0::RadioIndicationType type,
+            const hidl_vec<config::V1_0::SimSlotStatus>& slotStatus) override;
+    Return<void> simSlotsStatusChanged_1_2(
+            V1_0::RadioIndicationType type,
+            const hidl_vec<config::V1_2::SimSlotStatus>& slotStatus) override;
+
+  public:
+    RadioConfigIndication(
+            std::shared_ptr<aidl::android::hardware::radio::config::IRadioConfigIndication> cb);
+};
+
+}  // namespace android::hardware::radio::compat
diff --git a/radio/aidl/compat/libradiocompat/config/RadioConfigResponse.cpp b/radio/aidl/compat/libradiocompat/config/RadioConfigResponse.cpp
new file mode 100644
index 0000000..7066ae4
--- /dev/null
+++ b/radio/aidl/compat/libradiocompat/config/RadioConfigResponse.cpp
@@ -0,0 +1,90 @@
+/*
+ * Copyright (C) 2021 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 "RadioConfigResponse.h"
+
+#include "commonStructs.h"
+#include "debug.h"
+#include "structs.h"
+
+#include "collections.h"
+
+#define RADIO_MODULE "ConfigResponse"
+
+namespace android::hardware::radio::compat {
+
+namespace aidl = ::aidl::android::hardware::radio::config;
+
+RadioConfigResponse::RadioConfigResponse(std::shared_ptr<aidl::IRadioConfigResponse> callback)
+    : mCallback(callback) {}
+
+Return<void> RadioConfigResponse::getSimSlotsStatusResponse(
+        const V1_0::RadioResponseInfo& info,
+        const hidl_vec<config::V1_0::SimSlotStatus>& slotStatus) {
+    LOG_CALL << info.serial;
+    mCallback->getSimSlotsStatusResponse(toAidl(info), toAidl(slotStatus));
+    return {};
+};
+
+Return<void> RadioConfigResponse::getSimSlotsStatusResponse_1_2(
+        const V1_0::RadioResponseInfo& info,
+        const hidl_vec<config::V1_2::SimSlotStatus>& slotStatus) {
+    LOG_CALL << info.serial;
+    mCallback->getSimSlotsStatusResponse(toAidl(info), toAidl(slotStatus));
+    return {};
+};
+
+Return<void> RadioConfigResponse::setSimSlotsMappingResponse(const V1_0::RadioResponseInfo& info) {
+    LOG_CALL << info.serial;
+    mCallback->setSimSlotsMappingResponse(toAidl(info));
+    return {};
+};
+
+Return<void> RadioConfigResponse::getPhoneCapabilityResponse(
+        const V1_0::RadioResponseInfo& info, const config::V1_1::PhoneCapability& phoneCapability) {
+    LOG_CALL << info.serial;
+    mCallback->getPhoneCapabilityResponse(toAidl(info), toAidl(phoneCapability));
+    return {};
+};
+
+Return<void> RadioConfigResponse::setPreferredDataModemResponse(
+        const V1_0::RadioResponseInfo& info) {
+    LOG_CALL << info.serial;
+    mCallback->setPreferredDataModemResponse(toAidl(info));
+    return {};
+};
+
+Return<void> RadioConfigResponse::setModemsConfigResponse(const V1_0::RadioResponseInfo& info) {
+    LOG_CALL << info.serial;
+    mCallback->setNumOfLiveModemsResponse(toAidl(info));
+    return {};
+};
+
+Return<void> RadioConfigResponse::getModemsConfigResponse(
+        const V1_0::RadioResponseInfo& info, const config::V1_1::ModemsConfig& modemsConfig) {
+    LOG_CALL << info.serial;
+    mCallback->getNumOfLiveModemsResponse(toAidl(info), modemsConfig.numOfLiveModems);
+    return {};
+};
+
+Return<void> RadioConfigResponse::getHalDeviceCapabilitiesResponse(
+        const V1_6::RadioResponseInfo& info, bool modemReducedFeatureSet1) {
+    LOG_CALL << info.serial;
+    mCallback->getHalDeviceCapabilitiesResponse(toAidl(info), modemReducedFeatureSet1);
+    return {};
+};
+
+}  // namespace android::hardware::radio::compat
diff --git a/radio/aidl/compat/libradiocompat/config/RadioConfigResponse.h b/radio/aidl/compat/libradiocompat/config/RadioConfigResponse.h
new file mode 100644
index 0000000..1461dd2
--- /dev/null
+++ b/radio/aidl/compat/libradiocompat/config/RadioConfigResponse.h
@@ -0,0 +1,48 @@
+/*
+ * Copyright (C) 2021 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.
+ */
+#pragma once
+
+#include <aidl/android/hardware/radio/config/IRadioConfigResponse.h>
+#include <android/hardware/radio/config/1.3/IRadioConfigResponse.h>
+
+namespace android::hardware::radio::compat {
+
+class RadioConfigResponse : public config::V1_3::IRadioConfigResponse {
+    std::shared_ptr<aidl::android::hardware::radio::config::IRadioConfigResponse> mCallback;
+
+    Return<void> getSimSlotsStatusResponse(
+            const V1_0::RadioResponseInfo& info,
+            const hidl_vec<config::V1_0::SimSlotStatus>& slotStatus) override;
+    Return<void> setSimSlotsMappingResponse(const V1_0::RadioResponseInfo& info) override;
+    Return<void> getPhoneCapabilityResponse(
+            const V1_0::RadioResponseInfo& info,
+            const config::V1_1::PhoneCapability& phoneCapability) override;
+    Return<void> setPreferredDataModemResponse(const V1_0::RadioResponseInfo& info) override;
+    Return<void> setModemsConfigResponse(const V1_0::RadioResponseInfo& info) override;
+    Return<void> getModemsConfigResponse(const V1_0::RadioResponseInfo& info,
+                                         const config::V1_1::ModemsConfig& modemsConfig) override;
+    Return<void> getSimSlotsStatusResponse_1_2(
+            const V1_0::RadioResponseInfo& info,
+            const hidl_vec<config::V1_2::SimSlotStatus>& slotStatus) override;
+    Return<void> getHalDeviceCapabilitiesResponse(const V1_6::RadioResponseInfo& info,
+                                                  bool modemReducedFeatureSet1) override;
+
+  public:
+    RadioConfigResponse(
+            std::shared_ptr<aidl::android::hardware::radio::config::IRadioConfigResponse> callback);
+};
+
+}  // namespace android::hardware::radio::compat
diff --git a/radio/aidl/compat/libradiocompat/config/structs.cpp b/radio/aidl/compat/libradiocompat/config/structs.cpp
new file mode 100644
index 0000000..9ba5623
--- /dev/null
+++ b/radio/aidl/compat/libradiocompat/config/structs.cpp
@@ -0,0 +1,69 @@
+/*
+ * Copyright (C) 2021 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 "structs.h"
+
+#include "collections.h"
+
+#include <android-base/logging.h>
+
+namespace android::hardware::radio::compat {
+
+namespace aidl = ::aidl::android::hardware::radio::config;
+
+hidl_vec<uint32_t> toHidl(const std::vector<aidl::SlotPortMapping>& slotMap) {
+    hidl_vec<uint32_t> out(slotMap.size());
+    for (const auto& el : slotMap) {
+        CHECK_GE(el.portId, 0);
+        CHECK_LT(static_cast<size_t>(el.portId), out.size());
+        out[el.portId] = el.physicalSlotId;
+    }
+    return out;
+}
+
+aidl::SimSlotStatus toAidl(const config::V1_0::SimSlotStatus& sst) {
+    return toAidl({sst, ""});
+}
+
+aidl::SimSlotStatus toAidl(const config::V1_2::SimSlotStatus& sst) {
+    const aidl::SimPortInfo portInfo = {
+            .iccId = sst.base.iccid,
+            .logicalSlotId = static_cast<int32_t>(sst.base.logicalSlotId),
+            .portActive = sst.base.slotState == config::V1_0::SlotState::ACTIVE,
+    };
+
+    return {
+            .cardState = static_cast<int32_t>(sst.base.cardState),
+            .atr = sst.base.atr,
+            .eid = sst.eid,
+            .portInfo = {portInfo},
+    };
+}
+
+uint8_t toAidl(const config::V1_1::ModemInfo& info) {
+    return info.modemId;
+}
+
+aidl::PhoneCapability toAidl(const config::V1_1::PhoneCapability& phoneCapability) {
+    return {
+            .maxActiveData = static_cast<int8_t>(phoneCapability.maxActiveData),
+            .maxActiveInternetData = static_cast<int8_t>(phoneCapability.maxActiveInternetData),
+            .isInternetLingeringSupported = phoneCapability.isInternetLingeringSupported,
+            .logicalModemIds = toAidl(phoneCapability.logicalModemList),
+    };
+}
+
+}  // namespace android::hardware::radio::compat
diff --git a/radio/aidl/compat/libradiocompat/config/structs.h b/radio/aidl/compat/libradiocompat/config/structs.h
new file mode 100644
index 0000000..b8a0385
--- /dev/null
+++ b/radio/aidl/compat/libradiocompat/config/structs.h
@@ -0,0 +1,39 @@
+/*
+ * Copyright (C) 2021 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.
+ */
+#pragma once
+
+#include <aidl/android/hardware/radio/config/PhoneCapability.h>
+#include <aidl/android/hardware/radio/config/SimSlotStatus.h>
+#include <aidl/android/hardware/radio/config/SlotPortMapping.h>
+#include <android/hardware/radio/config/1.1/types.h>
+#include <android/hardware/radio/config/1.2/types.h>
+
+namespace android::hardware::radio::compat {
+
+hidl_vec<uint32_t>  //
+toHidl(const std::vector<aidl::android::hardware::radio::config::SlotPortMapping>& slotMap);
+
+aidl::android::hardware::radio::config::SimSlotStatus  //
+toAidl(const config::V1_0::SimSlotStatus& sst);
+aidl::android::hardware::radio::config::SimSlotStatus  //
+toAidl(const config::V1_2::SimSlotStatus& sst);
+
+uint8_t toAidl(const config::V1_1::ModemInfo& info);
+
+aidl::android::hardware::radio::config::PhoneCapability  //
+toAidl(const config::V1_1::PhoneCapability& pc);
+
+}  // namespace android::hardware::radio::compat
diff --git a/radio/aidl/compat/libradiocompat/debug.h b/radio/aidl/compat/libradiocompat/debug.h
new file mode 100644
index 0000000..cb773bf
--- /dev/null
+++ b/radio/aidl/compat/libradiocompat/debug.h
@@ -0,0 +1,35 @@
+/*
+ * Copyright (C) 2021 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.
+ */
+#pragma once
+
+#include <android-base/logging.h>
+
+namespace android::hardware::radio::compat {
+
+namespace debug {
+
+static constexpr bool kSuperVerbose = true;
+
+#define LOG_CALL \
+    if constexpr (debug::kSuperVerbose) LOG(VERBOSE) << (RADIO_MODULE ".") << __func__ << ' '
+
+}  // namespace debug
+
+inline std::ostream& operator<<(std::ostream& os, const V1_0::RadioIndicationType& type) {
+    return os << static_cast<int>(type);
+}
+
+}  // namespace android::hardware::radio::compat
diff --git a/radio/aidl/compat/libradiocompat/include/libradiocompat/RadioConfig.h b/radio/aidl/compat/libradiocompat/include/libradiocompat/RadioConfig.h
new file mode 100644
index 0000000..31ad207
--- /dev/null
+++ b/radio/aidl/compat/libradiocompat/include/libradiocompat/RadioConfig.h
@@ -0,0 +1,66 @@
+/*
+ * Copyright (C) 2021 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.
+ */
+#pragma once
+
+#include <aidl/android/hardware/radio/config/BnRadioConfig.h>
+#include <android/hardware/radio/config/1.2/IRadioConfigIndication.h>
+#include <android/hardware/radio/config/1.3/IRadioConfig.h>
+#include <android/hardware/radio/config/1.3/IRadioConfigResponse.h>
+
+namespace android::hardware::radio::compat {
+
+/**
+ * HAL translator from HIDL IRadioConfig to AIDL IRadioConfig.
+ *
+ * This class wraps existing HIDL implementation (either a binder stub or real
+ * class implementing the HAL) and implements AIDL HAL. It's up to the caller to
+ * fetch source implementation and publish resulting HAL instance.
+ */
+class RadioConfig : public aidl::android::hardware::radio::config::BnRadioConfig {
+    sp<config::V1_1::IRadioConfig> mHal1_1;
+    sp<config::V1_3::IRadioConfig> mHal1_3;
+
+    sp<config::V1_3::IRadioConfigResponse> mRadioConfigResponse;
+    sp<config::V1_2::IRadioConfigIndication> mRadioConfigIndication;
+
+    ::ndk::ScopedAStatus getHalDeviceCapabilities(int32_t serial) override;
+    ::ndk::ScopedAStatus getNumOfLiveModems(int32_t serial) override;
+    ::ndk::ScopedAStatus getPhoneCapability(int32_t serial) override;
+    ::ndk::ScopedAStatus getSimSlotsStatus(int32_t serial) override;
+    ::ndk::ScopedAStatus setNumOfLiveModems(int32_t serial, int8_t numOfLiveModems) override;
+    ::ndk::ScopedAStatus setPreferredDataModem(int32_t serial, int8_t modemId) override;
+    ::ndk::ScopedAStatus setResponseFunctions(
+            const std::shared_ptr<aidl::android::hardware::radio::config::IRadioConfigResponse>&
+                    radioConfigResponse,
+            const std::shared_ptr<aidl::android::hardware::radio::config::IRadioConfigIndication>&
+                    radioConfigIndication) override;
+    ::ndk::ScopedAStatus setSimSlotsMapping(
+            int32_t serial,
+            const std::vector<aidl::android::hardware::radio::config::SlotPortMapping>& slotMap)
+            override;
+
+    config::V1_3::IRadioConfigResponse& respond();
+
+  public:
+    /**
+     * Constructs AIDL IRadioConfig instance wrapping existing HIDL IRadioConfig instance.
+     *
+     * \param hidlHal existing HIDL IRadioConfig HAL instance
+     */
+    RadioConfig(sp<config::V1_1::IRadioConfig> hidlHal);
+};
+
+}  // namespace android::hardware::radio::compat
diff --git a/radio/aidl/compat/service/Android.bp b/radio/aidl/compat/service/Android.bp
new file mode 100644
index 0000000..f708b84
--- /dev/null
+++ b/radio/aidl/compat/service/Android.bp
@@ -0,0 +1,51 @@
+// Copyright (C) 2021 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 {
+    // See: http://go/android-license-faq
+    // A large-scale-change added 'default_applicable_licenses' to import
+    // all of the 'license_kinds' from "hardware_interfaces_license"
+    // to get the below license kinds:
+    //   SPDX-license-identifier-Apache-2.0
+    default_applicable_licenses: ["hardware_interfaces_license"],
+}
+
+cc_binary {
+    name: "android.hardware.radio-service.compat",
+    relative_install_path: "hw",
+    init_rc: ["radio-compat.rc"],
+    vintf_fragments: ["radio-compat.xml"],
+    vendor: true,
+    cflags: [
+        "-Wall",
+        "-Wextra",
+        "-DANDROID_UTILS_REF_BASE_DISABLE_IMPLICIT_CONSTRUCTION",
+    ],
+    shared_libs: [
+        "android.hardware.radio-library.compat",
+        "android.hardware.radio.config-V1-ndk",
+        "android.hardware.radio.config@1.0",
+        "android.hardware.radio.config@1.1",
+        "android.hardware.radio.config@1.2",
+        "android.hardware.radio.config@1.3",
+        "libbase",
+        "libbinder_ndk",
+        "libhidlbase",
+        "libutils",
+    ],
+    srcs: [
+        "hidl-utils.cpp",
+        "service.cpp",
+    ],
+}
diff --git a/radio/aidl/compat/service/hidl-utils.cpp b/radio/aidl/compat/service/hidl-utils.cpp
new file mode 100644
index 0000000..d894966
--- /dev/null
+++ b/radio/aidl/compat/service/hidl-utils.cpp
@@ -0,0 +1,36 @@
+/*
+ * Copyright (C) 2021 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 "hidl-utils.h"
+
+#include <android-base/logging.h>
+
+namespace android::hardware::hidl_utils {
+
+class HalDeathRecipient : public hidl_death_recipient {
+    void serviceDied(uint64_t /* cookie */, const wp<hidl::base::V1_0::IBase>& /* who */) override {
+        LOG(FATAL) << "One of the linked HALs died. Restarting...";
+    }
+};
+
+static const auto gHalDeathRecipient = sp<HalDeathRecipient>::make();
+
+void linkDeathToDeath(sp<::android::hidl::base::V1_0::IBase> hal) {
+    const auto linkStatus = hal->linkToDeath(gHalDeathRecipient, 0);
+    CHECK(linkStatus.withDefault(false)) << "Failed to link to HAL death";
+}
+
+}  // namespace android::hardware::hidl_utils
diff --git a/radio/aidl/compat/service/hidl-utils.h b/radio/aidl/compat/service/hidl-utils.h
new file mode 100644
index 0000000..3f81a9b
--- /dev/null
+++ b/radio/aidl/compat/service/hidl-utils.h
@@ -0,0 +1,30 @@
+/*
+ * Copyright (C) 2021 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.
+ */
+
+#pragma once
+
+#include <android/hidl/base/1.0/IBase.h>
+
+namespace android::hardware::hidl_utils {
+
+/**
+ * Link to a given HALs death and restart the current process in such a case.
+ *
+ * \param hal HAL to which death to link
+ */
+void linkDeathToDeath(sp<hidl::base::V1_0::IBase> hal);
+
+}  // namespace android::hardware::hidl_utils
diff --git a/radio/aidl/compat/service/radio-compat.rc b/radio/aidl/compat/service/radio-compat.rc
new file mode 100644
index 0000000..a159876
--- /dev/null
+++ b/radio/aidl/compat/service/radio-compat.rc
@@ -0,0 +1,4 @@
+service vendor.radio-compat /vendor/bin/hw/android.hardware.radio-service.compat
+    class hal
+    user nobody
+    group system
diff --git a/radio/aidl/compat/service/radio-compat.xml b/radio/aidl/compat/service/radio-compat.xml
new file mode 100644
index 0000000..60f8ff5
--- /dev/null
+++ b/radio/aidl/compat/service/radio-compat.xml
@@ -0,0 +1,6 @@
+<manifest version="1.0" type="device">
+    <hal format="aidl">
+        <name>android.hardware.radio.config</name>
+        <fqname>IRadioConfig/default</fqname>
+    </hal>
+</manifest>
diff --git a/radio/aidl/compat/service/service.cpp b/radio/aidl/compat/service/service.cpp
new file mode 100644
index 0000000..c177dd1
--- /dev/null
+++ b/radio/aidl/compat/service/service.cpp
@@ -0,0 +1,60 @@
+/*
+ * Copyright (C) 2021 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 "hidl-utils.h"
+
+#include <android-base/logging.h>
+#include <android/binder_manager.h>
+#include <android/binder_process.h>
+#include <libradiocompat/RadioConfig.h>
+
+namespace android::hardware::radio::service {
+
+using namespace std::string_literals;
+
+static std::vector<std::shared_ptr<ndk::ICInterface>> gPublishedHals;
+
+static void publishRadioConfig() {
+    auto hidlHal = config::V1_1::IRadioConfig::getService();
+    CHECK(hidlHal) << "HIDL IRadioConfig not present in VINTF";
+
+    hidl_utils::linkDeathToDeath(hidlHal);
+
+    auto aidlHal = ndk::SharedRefBase::make<compat::RadioConfig>(hidlHal);
+    gPublishedHals.push_back(aidlHal);
+    const auto instance = compat::RadioConfig::descriptor + "/default"s;
+    const auto status = AServiceManager_addService(aidlHal->asBinder().get(), instance.c_str());
+    CHECK_EQ(status, STATUS_OK);
+}
+
+static void main() {
+    base::SetDefaultTag("radiocompat");
+    base::SetMinimumLogSeverity(base::VERBOSE);
+    LOG(DEBUG) << "Radio HAL compat service starting...";
+
+    publishRadioConfig();
+
+    LOG(DEBUG) << "Radio HAL compat service is operational";
+    ABinderProcess_joinThreadPool();
+    LOG(FATAL) << "Radio HAL compat service has stopped";
+}
+
+}  // namespace android::hardware::radio::service
+
+int main() {
+    android::hardware::radio::service::main();
+    return EXIT_FAILURE;  // should not reach
+}