diff --git a/src/main/java/net/fabricmc/loom/task/launch/GenerateDLIConfigTask.java b/src/main/java/net/fabricmc/loom/task/launch/GenerateDLIConfigTask.java
index 0edf757c..895ae27e 100644
--- a/src/main/java/net/fabricmc/loom/task/launch/GenerateDLIConfigTask.java
+++ b/src/main/java/net/fabricmc/loom/task/launch/GenerateDLIConfigTask.java
@@ -44,6 +44,7 @@ import net.fabricmc.loom.configuration.launch.LaunchProviderSettings;
 import net.fabricmc.loom.configuration.providers.minecraft.MinecraftVersionMeta;
 import net.fabricmc.loom.configuration.providers.minecraft.mapped.MappedMinecraftProvider;
 import net.fabricmc.loom.task.AbstractLoomTask;
+import net.fabricmc.loom.util.Constants;
 import net.fabricmc.loom.util.PropertyUtil;
 import net.fabricmc.loom.util.gradle.SourceSetHelper;
 
@@ -95,9 +96,19 @@ public abstract class GenerateDLIConfigTask extends AbstractLoomTask {
 		}
 
 		if (getExtension().isForge()) {
+			// Find the mapping files for Unprotect to use for figuring out
+			// which classes are from Minecraft.
+			String unprotectMappings = getProject().getConfigurations()
+					.getByName(Constants.Configurations.MAPPINGS_FINAL)
+					.resolve()
+					.stream()
+					.map(File::getAbsolutePath)
+					.collect(Collectors.joining(File.pathSeparator));
+
 			launchConfig
 					// Should match YarnNamingService.PATH_TO_MAPPINGS in forge-runtime
 					.property("fabric.yarnWithSrg.path", getExtension().getMappingsProvider().tinyMappingsWithSrg.toAbsolutePath().toString())
+					.property("unprotect.mappings", unprotectMappings)
 
 					.argument("data", "--all")
 					.argument("data", "--mod")
diff --git a/src/main/java/net/fabricmc/loom/util/Constants.java b/src/main/java/net/fabricmc/loom/util/Constants.java
index 37917bb7..7b69784f 100644
--- a/src/main/java/net/fabricmc/loom/util/Constants.java
+++ b/src/main/java/net/fabricmc/loom/util/Constants.java
@@ -148,7 +148,7 @@ public class Constants {
 			public static final String FORGE_RUNTIME = "1.1.3";
 			public static final String ACCESS_TRANSFORMERS = "3.0.1";
 			public static final String ACCESS_TRANSFORMERS_NEW = "8.0.5";
-			public static final String UNPROTECT = "1.0.0";
+			public static final String UNPROTECT = "1.2.0";
 			public static final String ASM = "9.3";
 
 			private Versions() {