diff --git a/Tethering/jarjar-rules.txt b/Tethering/jarjar-rules.txt
index c6efa41..e90a2cc 100644
--- a/Tethering/jarjar-rules.txt
+++ b/Tethering/jarjar-rules.txt
@@ -8,7 +8,6 @@
 rule com.android.internal.util.IndentingPrintWriter.java* com.android.networkstack.tethering.util.IndentingPrintWriter.java@1
 rule com.android.internal.util.IState.java* com.android.networkstack.tethering.util.IState.java@1
 rule com.android.internal.util.MessageUtils* com.android.networkstack.tethering.util.MessageUtils@1
-rule com.android.internal.util.Preconditions* com.android.networkstack.tethering.util.Preconditions@1
 rule com.android.internal.util.State* com.android.networkstack.tethering.util.State@1
 rule com.android.internal.util.StateMachine* com.android.networkstack.tethering.util.StateMachine@1
 rule com.android.internal.util.TrafficStatsConstants* com.android.networkstack.tethering.util.TrafficStatsConstants@1
diff --git a/Tethering/src/com/android/networkstack/tethering/UpstreamNetworkMonitor.java b/Tethering/src/com/android/networkstack/tethering/UpstreamNetworkMonitor.java
index 25ddce4..320427c 100644
--- a/Tethering/src/com/android/networkstack/tethering/UpstreamNetworkMonitor.java
+++ b/Tethering/src/com/android/networkstack/tethering/UpstreamNetworkMonitor.java
@@ -43,7 +43,6 @@
 import android.util.SparseIntArray;
 
 import com.android.internal.annotations.VisibleForTesting;
-import com.android.internal.util.Preconditions;
 import com.android.internal.util.StateMachine;
 
 import java.util.HashMap;
@@ -591,7 +590,9 @@
         // Map from type to transports.
         final int notFound = -1;
         final int transport = sLegacyTypeToTransport.get(type, notFound);
-        Preconditions.checkArgument(transport != notFound, "unknown legacy type: " + type);
+        if (transport == notFound) {
+            throw new IllegalArgumentException("unknown legacy type: " + type);
+        }
         builder.addTransportType(transport);
 
         if (type == TYPE_MOBILE_DUN) {
diff --git a/Tethering/tests/unit/jarjar-rules.txt b/Tethering/tests/unit/jarjar-rules.txt
index 921fbed..1ea56cd 100644
--- a/Tethering/tests/unit/jarjar-rules.txt
+++ b/Tethering/tests/unit/jarjar-rules.txt
@@ -4,7 +4,6 @@
 rule com.android.internal.util.IndentingPrintWriter.java* com.android.networkstack.tethering.util.IndentingPrintWriter.java@1
 rule com.android.internal.util.IState.java* com.android.networkstack.tethering.util.IState.java@1
 rule com.android.internal.util.MessageUtils* com.android.networkstack.tethering.util.MessageUtils@1
-rule com.android.internal.util.Preconditions* com.android.networkstack.tethering.util.Preconditions@1
 rule com.android.internal.util.State* com.android.networkstack.tethering.util.State@1
 rule com.android.internal.util.StateMachine* com.android.networkstack.tethering.util.StateMachine@1
 rule com.android.internal.util.TrafficStatsConstants* com.android.networkstack.tethering.util.TrafficStatsConstants@1