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/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},
     };
 }