diff --git a/public/feather_diff.js b/public/feather_diff.js
index 51af7e1..8c8d74c 100644
--- a/public/feather_diff.js
+++ b/public/feather_diff.js
@@ -10,14 +10,20 @@ import {
 import * as tiny from "./tiny_mappings.js";
 
 (async () => {
-  const minecraftStableVersions = await getMinecraftStableVersions("gen1");
-  const minecraftAllVersions = await getMinecraftVersions("gen1");
+  let minecraftStableVersions = await getMinecraftStableVersions("gen1");
+  let minecraftAllVersions = await getMinecraftVersions("gen1");
 
   let possibleVersions;
 
+  const genSelectorRadios = {
+    gen1: document.getElementById("generation-gen1"),
+    gen2: document.getElementById("generation-gen2")
+  }
+
   const versionSelectorInput = document.getElementById("mc-version");
   const versionListElement = document.getElementById("version-list");
   const allowSnapshotsCheck = document.getElementById("allow-snapshots");
+  const featherGenSelector = document.getElementById("calamus-gen-selectors");
 
   const buildSourceElement = document.getElementById("build-source");
   const buildTargetElement = document.getElementById("build-target");
@@ -29,7 +35,8 @@ import * as tiny from "./tiny_mappings.js";
     if (
       possibleVersions.some((version) => versionSelectorInput.value === version)
     ) {
-      await getFeatherVersionMeta("gen1", versionSelectorInput.value).then(
+      const gen = Object.entries(genSelectorRadios).find(([_, button]) => button.checked)[0];
+      await getFeatherVersionMeta(gen, versionSelectorInput.value).then(
         (featherVersionMeta) => {
           buildSourceElement.innerHTML = "";
           buildTargetElement.innerHTML = "";
@@ -47,11 +54,16 @@ import * as tiny from "./tiny_mappings.js";
 
       // Hide the diff viewer bc the source and target builds are the same
       diffViewerElement.style.display = "none";
+    } else {
+      buildSourceElement.innerHTML = "";
+      buildTargetElement.innerHTML = "";
+      diffViewerElement.style.display = "none";
     }
   }
 
   async function getTinyMappings(version) {
-    let arrayBuf = await getFeatherBuildMaven(version)
+    const gen = Object.entries(genSelectorRadios).find(([_, button]) => button.checked)[0];
+    let arrayBuf = await getFeatherBuildMaven(gen, version)
       .then((response) => response.blob()) // Get response as a Blob
       .then(async (blob) => {
         const arrayBuffer = await blob.arrayBuffer(); // Convert Blob to ArrayBuffer
@@ -142,14 +154,17 @@ import * as tiny from "./tiny_mappings.js";
   );
 
   allowSnapshotsCheck.addEventListener("change", (_) => {
-    if (allowSnapshotsCheck.checked) {
-      possibleVersions = minecraftAllVersions;
-    } else {
-      possibleVersions = minecraftStableVersions;
-    }
     updateVersionList();
   });
 
+  featherGenSelector.addEventListener("change", async (e) => {
+    const gen = Object.entries(genSelectorRadios).find(([_, button]) => button === e.target)[0];
+    minecraftStableVersions = await getMinecraftStableVersions(gen);
+    minecraftAllVersions = await getMinecraftVersions(gen);
+
+    updateVersionList();
+  })
+
   buildSourceElement.addEventListener(
     "change",
     async (_) => await updateFeatherDiff(),
@@ -165,17 +180,21 @@ import * as tiny from "./tiny_mappings.js";
   });
 
   function updateVersionList() {
-    const list = possibleVersions;
+    if (allowSnapshotsCheck.checked) {
+      possibleVersions = minecraftAllVersions;
+    } else {
+      possibleVersions = minecraftStableVersions;
+    }
+
     while (versionListElement.firstChild)
       versionListElement.removeChild(versionListElement.lastChild);
-    list.forEach((e) => {
+    possibleVersions.forEach((e) => {
       const opt = new Option();
       opt.value = e;
       versionListElement.appendChild(opt);
     });
   }
 
-  possibleVersions = minecraftStableVersions;
   updateVersionList();
   await updateFeatherBuilds();
 })();
\ No newline at end of file
diff --git a/public/meta_maven_utils.js b/public/meta_maven_utils.js
index a3e05cd..5daca3a 100644
--- a/public/meta_maven_utils.js
+++ b/public/meta_maven_utils.js
@@ -143,7 +143,21 @@ function makeOrnitheMavenUrl(...pathComponents) {
     return makeMavenUrl("net/ornithemc", ...pathComponents);
 }
 
-export async function getFeatherBuildMaven(version) {
-    const url = makeOrnitheMavenUrl("feather", version, "feather-" + version + "-tiny.gz");
+export async function getFeatherBuildMaven(ornitheGen, version) {
+    let feather;
+    switch (ornitheGen) {
+        case "gen1": {
+            feather = "feather";
+            break;
+        }
+        case "gen2": {
+            feather = "feather-gen2";
+            break;
+        }
+        default: {
+            throw new Error("Invalid generation: " + ornitheGen);
+        }
+    }
+    const url = makeOrnitheMavenUrl(feather, version, "feather-" + version + "-tiny.gz");
     return await fetch(url);
 }
diff --git a/src/pages/featherDiff.astro b/src/pages/featherDiff.astro
index 6081fbf..22950a6 100644
--- a/src/pages/featherDiff.astro
+++ b/src/pages/featherDiff.astro
@@ -16,6 +16,15 @@ import Layout from "../layouts/Layout.astro";
                 <label for="allow-snapshots">Include Snapshots</label>
             </fieldset>
 
+            <fieldset id="calamus-gen-selectors">
+                <legend>Select a Calamus (Intermediary) Generation</legend>
+                <input type="radio" id="generation-gen1" name="calamus-generation" checked />
+                <label for="generation-gen1">Gen1</label>
+
+                <input type="radio" id="generation-gen2" name="calamus-generation" />
+                <label for="generation-gen2">Gen2</label>
+            </fieldset>
+
             <label for="mc-version">Game version</label>
             <input type="text" id="mc-version" list="version-list" value="1.7.2" />
             <datalist id="version-list">