diff --git a/src/main/java/dan200/computercraft/shared/PocketUpgrades.java b/src/main/java/dan200/computercraft/shared/PocketUpgrades.java
index 2358d28be..2bb1a0f61 100644
--- a/src/main/java/dan200/computercraft/shared/PocketUpgrades.java
+++ b/src/main/java/dan200/computercraft/shared/PocketUpgrades.java
@@ -7,7 +7,9 @@
 
 import dan200.computercraft.ComputerCraft;
 import dan200.computercraft.api.pocket.IPocketUpgrade;
+import it.unimi.dsi.fastutil.objects.Object2ObjectLinkedOpenCustomHashMap;
 import net.minecraft.item.ItemStack;
+import net.minecraft.util.Util;
 import net.minecraftforge.fml.ModContainer;
 import net.minecraftforge.fml.ModLoadingContext;
 
@@ -18,7 +20,7 @@
 public final class PocketUpgrades
 {
     private static final Map<String, IPocketUpgrade> upgrades = new HashMap<>();
-    private static final IdentityHashMap<IPocketUpgrade, String> upgradeOwners = new IdentityHashMap<>();
+    private static final Map<IPocketUpgrade, String> upgradeOwners = new Object2ObjectLinkedOpenCustomHashMap<>( Util.identityStrategy() );
 
     private PocketUpgrades() {}
 
diff --git a/src/main/java/dan200/computercraft/shared/TurtleUpgrades.java b/src/main/java/dan200/computercraft/shared/TurtleUpgrades.java
index c13774b5a..6f5b3b3c2 100644
--- a/src/main/java/dan200/computercraft/shared/TurtleUpgrades.java
+++ b/src/main/java/dan200/computercraft/shared/TurtleUpgrades.java
@@ -8,12 +8,17 @@
 import dan200.computercraft.ComputerCraft;
 import dan200.computercraft.api.turtle.ITurtleUpgrade;
 import dan200.computercraft.shared.computer.core.ComputerFamily;
+import it.unimi.dsi.fastutil.objects.Object2ObjectLinkedOpenCustomHashMap;
 import net.minecraft.item.ItemStack;
+import net.minecraft.util.Util;
 import net.minecraftforge.fml.ModLoadingContext;
 
 import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
-import java.util.*;
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Objects;
 import java.util.stream.Stream;
 
 public final class TurtleUpgrades
@@ -37,7 +42,7 @@ private static class Wrapper
     private static ITurtleUpgrade[] vanilla;
 
     private static final Map<String, ITurtleUpgrade> upgrades = new HashMap<>();
-    private static final IdentityHashMap<ITurtleUpgrade, Wrapper> wrappers = new IdentityHashMap<>();
+    private static final Map<ITurtleUpgrade, Wrapper> wrappers = new Object2ObjectLinkedOpenCustomHashMap<>( Util.identityStrategy() );
     private static boolean needsRebuild;
 
     private TurtleUpgrades() {}