diff --git a/health/aidl/default/Android.bp b/health/aidl/default/Android.bp
index 8aa7638..8eab997 100644
--- a/health/aidl/default/Android.bp
+++ b/health/aidl/default/Android.bp
@@ -120,6 +120,15 @@
     },
 }
 
+// Users of libhealth_aidl_impl should use this defaults.
+cc_defaults {
+    name: "libhealth_aidl_impl_user",
+    defaults: [
+        "libhealth_aidl_common_defaults",
+        "libhealth_aidl_charger_defaults",
+    ],
+}
+
 // AIDL version of android.hardware.health@2.1-service.
 // Default binder service of the health HAL.
 cc_defaults {
@@ -127,8 +136,7 @@
     relative_install_path: "hw",
     vintf_fragments: ["android.hardware.health-service.example.xml"],
     defaults: [
-        "libhealth_aidl_common_defaults",
-        "libhealth_aidl_charger_defaults",
+        "libhealth_aidl_impl_user",
     ],
     static_libs: [
         "libhealth_aidl_impl",
diff --git a/radio/aidl/compat/libradiocompat/RadioResponse.cpp b/radio/aidl/compat/libradiocompat/RadioResponse.cpp
index dbeb68a..dab70cc 100644
--- a/radio/aidl/compat/libradiocompat/RadioResponse.cpp
+++ b/radio/aidl/compat/libradiocompat/RadioResponse.cpp
@@ -26,7 +26,10 @@
 
 Return<void> RadioResponse::acknowledgeRequest(int32_t serial) {
     LOG_CALL << serial;
-    // TODO(b/203699028): send to correct requestor or confirm if spam is not a problem
+    /* We send ACKs to all callbacks instead of the one requested it to make implementation simpler.
+     * If it turns out to be a problem, we would have to track where serials come from and make sure
+     * this tracking data (e.g. a map) doesn't grow indefinitely.
+     */
     if (mDataCb) mDataCb.get()->acknowledgeRequest(serial);
     if (mMessagingCb) mMessagingCb.get()->acknowledgeRequest(serial);
     if (mModemCb) mModemCb.get()->acknowledgeRequest(serial);
diff --git a/radio/aidl/compat/libradiocompat/config/RadioConfig.cpp b/radio/aidl/compat/libradiocompat/config/RadioConfig.cpp
index 5b22dbe..b450418 100644
--- a/radio/aidl/compat/libradiocompat/config/RadioConfig.cpp
+++ b/radio/aidl/compat/libradiocompat/config/RadioConfig.cpp
@@ -20,6 +20,8 @@
 #include "debug.h"
 #include "structs.h"
 
+#include "collections.h"
+
 #define RADIO_MODULE "Config"
 
 namespace android::hardware::radio::compat {
diff --git a/radio/aidl/compat/libradiocompat/config/structs.cpp b/radio/aidl/compat/libradiocompat/config/structs.cpp
index 9ba5623..39ad944 100644
--- a/radio/aidl/compat/libradiocompat/config/structs.cpp
+++ b/radio/aidl/compat/libradiocompat/config/structs.cpp
@@ -24,14 +24,11 @@
 
 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;
+uint32_t toHidl(const aidl::SlotPortMapping& slotPortMapping) {
+    if (slotPortMapping.portId != 0) {
+        LOG(ERROR) << "Port ID " << slotPortMapping.portId << " != 0 not supported by HIDL HAL";
     }
-    return out;
+    return slotPortMapping.physicalSlotId;
 }
 
 aidl::SimSlotStatus toAidl(const config::V1_0::SimSlotStatus& sst) {
diff --git a/radio/aidl/compat/libradiocompat/config/structs.h b/radio/aidl/compat/libradiocompat/config/structs.h
index b8a0385..6ea4e4a 100644
--- a/radio/aidl/compat/libradiocompat/config/structs.h
+++ b/radio/aidl/compat/libradiocompat/config/structs.h
@@ -23,8 +23,7 @@
 
 namespace android::hardware::radio::compat {
 
-hidl_vec<uint32_t>  //
-toHidl(const std::vector<aidl::android::hardware::radio::config::SlotPortMapping>& slotMap);
+uint32_t toHidl(const aidl::android::hardware::radio::config::SlotPortMapping& slotPortMapping);
 
 aidl::android::hardware::radio::config::SimSlotStatus  //
 toAidl(const config::V1_0::SimSlotStatus& sst);
diff --git a/radio/aidl/compat/libradiocompat/network/RadioNetwork.cpp b/radio/aidl/compat/libradiocompat/network/RadioNetwork.cpp
index d3b6002..22b9ede 100644
--- a/radio/aidl/compat/libradiocompat/network/RadioNetwork.cpp
+++ b/radio/aidl/compat/libradiocompat/network/RadioNetwork.cpp
@@ -254,7 +254,13 @@
 ScopedAStatus RadioNetwork::setSignalStrengthReportingCriteria(
         int32_t serial, const std::vector<aidl::SignalThresholdInfo>& infos) {
     LOG_CALL << serial;
-    // TODO(b/203699028): how about other infos?
+    if (infos.size() == 0) {
+        LOG(ERROR) << "Threshold info array is empty - dropping setSignalStrengthReportingCriteria";
+        return ok();
+    }
+    if (infos.size() > 1) {
+        LOG(WARNING) << "Multi-element reporting criteria are not supported with HIDL HAL";
+    }
     mHal1_5->setSignalStrengthReportingCriteria_1_5(serial, toHidl(infos[0]),
                                                     V1_5::AccessNetwork(infos[0].ran));
     return ok();
@@ -291,18 +297,17 @@
     return ok();
 }
 
-// TODO(b/210498497): is there a cleaner way to send a response back to Android, even though these
-// methods must never be called?
-ScopedAStatus RadioNetwork::setUsageSetting(
-        int32_t ser, ::aidl::android::hardware::radio::network::UsageSetting) {
-    LOG_CALL << ser;
+ScopedAStatus RadioNetwork::setUsageSetting(int32_t serial, aidl::UsageSetting) {
+    LOG_CALL << serial;
     LOG(ERROR) << "setUsageSetting is unsupported by HIDL HALs";
+    respond()->setUsageSettingResponse(notSupported(serial));
     return ok();
 }
 
-ScopedAStatus RadioNetwork::getUsageSetting(int32_t ser) {
-    LOG_CALL << ser;
+ScopedAStatus RadioNetwork::getUsageSetting(int32_t serial) {
+    LOG_CALL << serial;
     LOG(ERROR) << "getUsageSetting is unsupported by HIDL HALs";
+    respond()->getUsageSettingResponse(notSupported(serial), {});  // {} = neither voice nor data
     return ok();
 }
 
diff --git a/radio/aidl/compat/libradiocompat/sim/structs.cpp b/radio/aidl/compat/libradiocompat/sim/structs.cpp
index 97a21a1..bfbff02 100644
--- a/radio/aidl/compat/libradiocompat/sim/structs.cpp
+++ b/radio/aidl/compat/libradiocompat/sim/structs.cpp
@@ -173,7 +173,6 @@
             .atr = status.base.base.atr,
             .iccid = status.base.base.iccid,
             .eid = status.base.eid,
-            // TODO(b/203699028): we don't know portId here (but we can get it from RadioConfig)
             .slotMap = {static_cast<int32_t>(status.base.base.physicalSlotId), 0},
     };
 }