feat(downloads): allow manual checkpoint/diffusion root override in download modal

locales/de.json

@@ -1563,6 +1563,10 @@
             "selectRootDirectory": "Wählen Sie ein Stammverzeichnis",
             "selectModelRoot": "Modell-Stammverzeichnis auswählen:",
             "selectTypeRoot": "{type}-Stammverzeichnis auswählen:",
+            "routingOverride": {
+                "label": "[TODO: Translate] Destination type:",
+                "tooltip": "[TODO: Translate] Auto-detected from the model metadata. Switch if it was misdetected; switching turns off \"Use Default Path\" for this download."
+            },
             "targetFolderPath": "Zielordnerpfad:",
             "browseFolders": "Ordner durchsuchen:",
             "createNewFolder": "Neuen Ordner erstellen",

locales/en.json

@@ -1563,6 +1563,10 @@
       "selectRootDirectory": "Select a root directory",
       "selectModelRoot": "Select Model Root:",
       "selectTypeRoot": "Select {type} Root:",
+      "routingOverride": {
+        "label": "Destination type:",
+        "tooltip": "Auto-detected from the model metadata. Switch if it was misdetected; switching turns off \"Use Default Path\" for this download."
+      },
       "targetFolderPath": "Target Folder Path:",
       "browseFolders": "Browse Folders:",
       "createNewFolder": "Create new folder",

locales/es.json

@@ -1563,6 +1563,10 @@
             "selectRootDirectory": "Selecciona un directorio raíz",
             "selectModelRoot": "Seleccionar raíz del modelo:",
             "selectTypeRoot": "Seleccionar raíz de {type}:",
+            "routingOverride": {
+                "label": "[TODO: Translate] Destination type:",
+                "tooltip": "[TODO: Translate] Auto-detected from the model metadata. Switch if it was misdetected; switching turns off \"Use Default Path\" for this download."
+            },
             "targetFolderPath": "Ruta de carpeta de destino:",
             "browseFolders": "Explorar carpetas:",
             "createNewFolder": "Crear nueva carpeta",

locales/fr.json

@@ -1563,6 +1563,10 @@
             "selectRootDirectory": "Sélectionner un répertoire racine",
             "selectModelRoot": "Sélectionner la racine du modèle :",
             "selectTypeRoot": "Sélectionner la racine {type} :",
+            "routingOverride": {
+                "label": "[TODO: Translate] Destination type:",
+                "tooltip": "[TODO: Translate] Auto-detected from the model metadata. Switch if it was misdetected; switching turns off \"Use Default Path\" for this download."
+            },
             "targetFolderPath": "Chemin du dossier cible :",
             "browseFolders": "Parcourir les dossiers :",
             "createNewFolder": "Créer un nouveau dossier",

locales/he.json

@@ -1563,6 +1563,10 @@
             "selectRootDirectory": "בחר ספריית שורש",
             "selectModelRoot": "בחר שורש מודל:",
             "selectTypeRoot": "בחר שורש {type}:",
+            "routingOverride": {
+                "label": "[TODO: Translate] Destination type:",
+                "tooltip": "[TODO: Translate] Auto-detected from the model metadata. Switch if it was misdetected; switching turns off \"Use Default Path\" for this download."
+            },
             "targetFolderPath": "נתיב תיקיית יעד:",
             "browseFolders": "דפדף בתיקיות:",
             "createNewFolder": "צור תיקייה חדשה",

locales/ja.json

@@ -1563,6 +1563,10 @@
             "selectRootDirectory": "ルートディレクトリを選択",
             "selectModelRoot": "モデルルートを選択：",
             "selectTypeRoot": "{type}ルートを選択：",
+            "routingOverride": {
+                "label": "[TODO: Translate] Destination type:",
+                "tooltip": "[TODO: Translate] Auto-detected from the model metadata. Switch if it was misdetected; switching turns off \"Use Default Path\" for this download."
+            },
             "targetFolderPath": "ターゲットフォルダパス：",
             "browseFolders": "フォルダを参照：",
             "createNewFolder": "新しいフォルダを作成",

locales/ko.json

@@ -1563,6 +1563,10 @@
             "selectRootDirectory": "루트 디렉토리를 선택하세요",
             "selectModelRoot": "모델 루트 선택:",
             "selectTypeRoot": "{type} 루트 선택:",
+            "routingOverride": {
+                "label": "[TODO: Translate] Destination type:",
+                "tooltip": "[TODO: Translate] Auto-detected from the model metadata. Switch if it was misdetected; switching turns off \"Use Default Path\" for this download."
+            },
             "targetFolderPath": "대상 폴더 경로:",
             "browseFolders": "폴더 탐색:",
             "createNewFolder": "새 폴더 만들기",

locales/ru.json

@@ -1563,6 +1563,10 @@
             "selectRootDirectory": "Выберите корневую папку",
             "selectModelRoot": "Выберите корень моделей:",
             "selectTypeRoot": "Выберите корень {type}:",
+            "routingOverride": {
+                "label": "[TODO: Translate] Destination type:",
+                "tooltip": "[TODO: Translate] Auto-detected from the model metadata. Switch if it was misdetected; switching turns off \"Use Default Path\" for this download."
+            },
             "targetFolderPath": "Путь к целевой папке:",
             "browseFolders": "Обзор папок:",
             "createNewFolder": "Создать новую папку",

locales/zh-CN.json

@@ -1563,6 +1563,10 @@
             "selectRootDirectory": "选择根目录",
             "selectModelRoot": "选择模型根目录：",
             "selectTypeRoot": "选择 {type} 根目录：",
+            "routingOverride": {
+                "label": "[TODO: Translate] Destination type:",
+                "tooltip": "[TODO: Translate] Auto-detected from the model metadata. Switch if it was misdetected; switching turns off \"Use Default Path\" for this download."
+            },
             "targetFolderPath": "目标文件夹路径：",
             "browseFolders": "浏览文件夹：",
             "createNewFolder": "新建文件夹",

locales/zh-TW.json

@@ -1563,6 +1563,10 @@
             "selectRootDirectory": "選擇根目錄",
             "selectModelRoot": "選擇模型根目錄：",
             "selectTypeRoot": "選擇 {type} 根目錄：",
+            "routingOverride": {
+                "label": "[TODO: Translate] Destination type:",
+                "tooltip": "[TODO: Translate] Auto-detected from the model metadata. Switch if it was misdetected; switching turns off \"Use Default Path\" for this download."
+            },
             "targetFolderPath": "目標資料夾路徑：",
             "browseFolders": "瀏覽資料夾：",
             "createNewFolder": "建立新資料夾",

static/css/components/modal/download-modal.css

@@ -1088,3 +1088,56 @@
 [data-theme="dark"] .batch-preview-group-body {
     background: var(--border-color);
 }
+
+
+/* Routing override segmented toggle (Checkpoint / Diffusion Model) shown on
+   the checkpoints page of the download modal when auto-routing can misdetect. */
+.routing-override-group {
+    margin-bottom: var(--space-2);
+}
+
+.routing-override-group label {
+    display: block;
+    margin-bottom: 8px;
+    color: var(--text-color);
+}
+
+.routing-override-toggle {
+    display: flex;
+    gap: 0;
+}
+
+.routing-override-option {
+    flex: 1;
+    padding: 6px 8px;
+    border: 1px solid var(--border-color);
+    background: var(--bg-color);
+    color: var(--text-color);
+    opacity: 0.75;
+    cursor: pointer;
+    transition: var(--transition-base);
+    font-size: 0.9em;
+}
+
+.routing-override-option:first-child {
+    border-radius: var(--border-radius-xs) 0 0 var(--border-radius-xs);
+    border-right: none;
+}
+
+.routing-override-option:last-child {
+    border-radius: 0 var(--border-radius-xs) var(--border-radius-xs) 0;
+}
+
+.routing-override-option:not(.active):hover,
+.routing-override-option:not(.active):focus-visible {
+    border-color: var(--lora-accent);
+    opacity: 1;
+}
+
+.routing-override-option.active {
+    background: var(--lora-accent);
+    color: white;
+    border-color: var(--lora-accent);
+    opacity: 1;
+    cursor: default;
+}

static/js/managers/DownloadManager.js

@@ -34,6 +34,9 @@ export class DownloadManager {
         this.selectedFolder = '';
         this.apiClient = null;
         this.useDefaultPath = false;
+        // Manual checkpoint/diffusion root override on the location step:
+        // null follows the auto classification, true/false is user-picked.
+        this._routingOverride = null;
 
         // Multi-file selection state: selectedFile stays the first selected
         // file for backward compatibility with single-file flows (#1058).
@@ -127,6 +130,11 @@ export class DownloadManager {
         // Default path toggle handler
         document.getElementById('useDefaultPath').addEventListener('change', this.handleToggleDefaultPath);
 
+        // Checkpoint/diffusion routing override toggle (checkpoints page only)
+        document.querySelectorAll('#routingOverrideGroup .routing-override-option').forEach(btn => {
+            btn.addEventListener('click', () => this.handleRoutingOverrideChange(btn.dataset.routing === 'diffusion'));
+        });
+
         // Auto-append newline after pasting a URL so users can paste multiple URLs in succession
         setupAutoNewlineOnPaste('modelUrl');
     }
@@ -180,6 +188,7 @@ export class DownloadManager {
         this.selectedFiles = [];
         this._lastDownloadError = null;
         this._isDiffusionModel = false;
+        this._routingOverride = null;
 
         this.selectedFolder = '';
         this.batchModels = [];
@@ -974,48 +983,12 @@ export class DownloadManager {
         try {
             this._isDiffusionModel = await this._resolveIsDiffusionModel();
             this._otherSubType = await this._resolveOtherSubType();
+            // Each location-step entry starts from the auto classification;
+            // the user can override it via the checkpoint/diffusion toggle.
+            this._routingOverride = null;
+            this._syncRoutingOverrideToggle();
 
-            let rootsData;
-            if (this._isDiffusionModel && this.apiClient.modelType === 'checkpoints') {
-                rootsData = await this.apiClient.fetchModelRoots('diffusion_model');
-            } else if (this.apiClient.modelType === 'other' && this._otherSubType) {
-                rootsData = await this.apiClient.fetchModelRoots(this._otherSubType);
-            } else {
-                // An undecidable other sub_type (null) intentionally lands
-                // here: fetchModelRoots() lists all other roots so the user
-                // can pick manually.
-                rootsData = await this.apiClient.fetchModelRoots();
-            }
-            const modelRoot = document.getElementById('modelRoot');
-            modelRoot.innerHTML = rootsData.roots.map(root =>
-                `<option value="${root}">${root}</option>`
-            ).join('');
-
-            let defaultRoot;
-            let subtypeDisplay;
-            if (this.apiClient.modelType === 'other') {
-                const otherDefaultRoots = state.global.settings.default_other_roots || {};
-                defaultRoot = this._otherSubType ? (otherDefaultRoots[this._otherSubType] || '') : '';
-                subtypeDisplay = this._otherSubType
-                    ? (MODEL_SUBTYPE_DISPLAY_NAMES[this._otherSubType] || this._otherSubType)
-                    : this.apiClient.apiConfig.config.displayName;
-            } else {
-                const singularType = this._isDiffusionModel
-                    ? 'unet'
-                    : this.apiClient.modelType.replace(/s$/, '');
-                const defaultRootKey = `default_${singularType}_root`;
-                defaultRoot = state.global.settings[defaultRootKey];
-                subtypeDisplay = this._isDiffusionModel ? 'Diffusion Model' : this.apiClient.apiConfig.config.displayName;
-            }
-            console.log('Default root:', defaultRoot);
-            console.log('Available roots:', rootsData.roots);
-            if (defaultRoot && rootsData.roots.includes(defaultRoot)) {
-                console.log(`Setting default root: ${defaultRoot}`);
-                modelRoot.value = defaultRoot;
-            }
-
-            document.getElementById('modelRootLabel').textContent =
-                translate('modals.download.selectTypeRoot', { type: subtypeDisplay });
+            await this._populateModelRoots();
 
             // Set autocomplete="off" on folderPath input
             const folderPathInput = document.getElementById('folderPath');
@@ -1035,6 +1008,7 @@ export class DownloadManager {
             });
 
             // Setup model root change handler
+            const modelRoot = document.getElementById('modelRoot');
             modelRoot.addEventListener('change', async () => {
                 await this.initializeFolderTree();
                 this.updateTargetPath();
@@ -1049,6 +1023,116 @@ export class DownloadManager {
         }
     }
 
+    /**
+     * Effective checkpoint/diffusion routing for the location step: the
+     * user's manual override when set, otherwise the auto classification.
+     */
+    _getEffectiveIsDiffusionModel() {
+        return this._routingOverride ?? this._isDiffusionModel;
+    }
+
+    /**
+     * Fetch the root list for the effective routing group and repopulate
+     * the root dropdown, preselecting the matching default root and
+     * updating the root label.
+     */
+    async _populateModelRoots() {
+        const isDiffusion = this._getEffectiveIsDiffusionModel();
+
+        let rootsData;
+        if (isDiffusion && this.apiClient.modelType === 'checkpoints') {
+            rootsData = await this.apiClient.fetchModelRoots('diffusion_model');
+        } else if (this.apiClient.modelType === 'other' && this._otherSubType) {
+            rootsData = await this.apiClient.fetchModelRoots(this._otherSubType);
+        } else {
+            // An undecidable other sub_type (null) intentionally lands
+            // here: fetchModelRoots() lists all other roots so the user
+            // can pick manually.
+            rootsData = await this.apiClient.fetchModelRoots();
+        }
+        const modelRoot = document.getElementById('modelRoot');
+        modelRoot.innerHTML = rootsData.roots.map(root =>
+            `<option value="${root}">${root}</option>`
+        ).join('');
+
+        let defaultRoot;
+        let subtypeDisplay;
+        if (this.apiClient.modelType === 'other') {
+            const otherDefaultRoots = state.global.settings.default_other_roots || {};
+            defaultRoot = this._otherSubType ? (otherDefaultRoots[this._otherSubType] || '') : '';
+            subtypeDisplay = this._otherSubType
+                ? (MODEL_SUBTYPE_DISPLAY_NAMES[this._otherSubType] || this._otherSubType)
+                : this.apiClient.apiConfig.config.displayName;
+        } else {
+            const singularType = isDiffusion
+                ? 'unet'
+                : this.apiClient.modelType.replace(/s$/, '');
+            const defaultRootKey = `default_${singularType}_root`;
+            defaultRoot = state.global.settings[defaultRootKey];
+            subtypeDisplay = isDiffusion ? 'Diffusion Model' : this.apiClient.apiConfig.config.displayName;
+        }
+        console.log('Default root:', defaultRoot);
+        console.log('Available roots:', rootsData.roots);
+        if (defaultRoot && rootsData.roots.includes(defaultRoot)) {
+            console.log(`Setting default root: ${defaultRoot}`);
+            modelRoot.value = defaultRoot;
+        }
+
+        document.getElementById('modelRootLabel').textContent =
+            translate('modals.download.selectTypeRoot', { type: subtypeDisplay });
+    }
+
+    /**
+     * Show the checkpoint/diffusion override toggle on the checkpoints page
+     * (hidden elsewhere) and reflect the effective routing on its options.
+     */
+    _syncRoutingOverrideToggle() {
+        const group = document.getElementById('routingOverrideGroup');
+        if (!group) return;
+        const isCheckpoints = this.apiClient.modelType === 'checkpoints';
+        group.style.display = isCheckpoints ? '' : 'none';
+        if (!isCheckpoints) return;
+
+        const effective = this._getEffectiveIsDiffusionModel();
+        group.querySelectorAll('.routing-override-option').forEach(btn => {
+            const active = (btn.dataset.routing === 'diffusion') === effective;
+            btn.classList.toggle('active', active);
+            btn.setAttribute('aria-pressed', active ? 'true' : 'false');
+        });
+    }
+
+    /**
+     * Handle the user switching the checkpoint/diffusion routing toggle.
+     * The override must never be silently ignored: the backend re-derives
+     * the routing group only under "use default path", so overriding turns
+     * that off for this session (the localStorage preference is left
+     * untouched) to guarantee the picked root is the actual destination.
+     */
+    async handleRoutingOverrideChange(isDiffusion) {
+        if (this.apiClient.modelType !== 'checkpoints') return;
+
+        const overridden = isDiffusion !== this._isDiffusionModel;
+        this._routingOverride = overridden ? isDiffusion : null;
+
+        if (overridden && this.useDefaultPath) {
+            this.useDefaultPath = false;
+            const toggleInput = document.getElementById('useDefaultPath');
+            if (toggleInput) {
+                toggleInput.checked = false;
+            }
+        }
+
+        this._syncRoutingOverrideToggle();
+
+        try {
+            await this._populateModelRoots();
+            await this.initializeFolderTree();
+            this.updatePathSelectionUI();
+        } catch (error) {
+            showToast('toast.downloads.loadError', { message: error.message }, 'error');
+        }
+    }
+
     /**
      * Decide whether this download routes to the diffusion model (unet)
      * roots rather than the checkpoint roots. The backend owns the routing
@@ -2554,13 +2638,13 @@ export class DownloadManager {
         const modelRoot = document.getElementById('modelRoot').value;
         const config = this.apiClient.apiConfig.config;
 
-        const subtypeDisplay = this._isDiffusionModel ? 'Diffusion Model' : config.displayName;
+        const subtypeDisplay = this._getEffectiveIsDiffusionModel() ? 'Diffusion Model' : config.displayName;
         let fullPath = modelRoot || translate('modals.download.selectTypeRoot', { type: subtypeDisplay });
 
         if (modelRoot) {
             if (this.useDefaultPath) {
                 try {
-                    const singularType = this._isDiffusionModel
+                    const singularType = this._getEffectiveIsDiffusionModel()
                         ? 'unet'
                         : this.apiClient.modelType.replace(/s$/, '');
                     const templates = state.global?.settings?.download_path_templates;

templates/components/modals/download_modal.html

@@ -80,6 +80,14 @@
                 </div>
 
                 <!-- Model Root Selection (always visible) -->
+                <div class="input-group routing-override-group" id="routingOverrideGroup" style="display: none;"
+                     title="{{ t('modals.download.routingOverride.tooltip') }}">
+                    <label id="routingOverrideLabel">{{ t('modals.download.routingOverride.label') }}</label>
+                    <div class="routing-override-toggle" role="group" aria-label="{{ t('modals.download.routingOverride.label') }}">
+                        <button type="button" class="routing-override-option" data-routing="checkpoint">{{ t('checkpoints.modelTypes.checkpoint') }}</button>
+                        <button type="button" class="routing-override-option" data-routing="diffusion">{{ t('checkpoints.modelTypes.diffusion_model') }}</button>
+                    </div>
+                </div>
                 <div class="input-group">
                     <label for="modelRoot" id="modelRootLabel">{{ t('modals.download.selectModelRoot') }}</label>
                     <select id="modelRoot"></select>

tests/frontend/managers/downloadManager.routingOverride.test.js

@@ -0,0 +1,209 @@
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';
+
+const {
+  DOWNLOAD_MANAGER_MODULE,
+  MODAL_MANAGER_MODULE,
+  UI_HELPERS_MODULE,
+  STATE_MODULE,
+  LOADING_MANAGER_MODULE,
+  API_FACTORY_MODULE,
+  STORAGE_HELPERS_MODULE,
+  FOLDER_TREE_MANAGER_MODULE,
+  I18N_HELPERS_MODULE,
+  SUMMARY_MODULE,
+  OTHER_MODELS_MODULE,
+} = vi.hoisted(() => ({
+  DOWNLOAD_MANAGER_MODULE: new URL('../../../static/js/managers/DownloadManager.js', import.meta.url).pathname,
+  MODAL_MANAGER_MODULE: new URL('../../../static/js/managers/ModalManager.js', import.meta.url).pathname,
+  UI_HELPERS_MODULE: new URL('../../../static/js/utils/uiHelpers.js', import.meta.url).pathname,
+  STATE_MODULE: new URL('../../../static/js/state/index.js', import.meta.url).pathname,
+  LOADING_MANAGER_MODULE: new URL('../../../static/js/managers/LoadingManager.js', import.meta.url).pathname,
+  API_FACTORY_MODULE: new URL('../../../static/js/api/modelApiFactory.js', import.meta.url).pathname,
+  STORAGE_HELPERS_MODULE: new URL('../../../static/js/utils/storageHelpers.js', import.meta.url).pathname,
+  FOLDER_TREE_MANAGER_MODULE: new URL('../../../static/js/components/FolderTreeManager.js', import.meta.url).pathname,
+  I18N_HELPERS_MODULE: new URL('../../../static/js/utils/i18nHelpers.js', import.meta.url).pathname,
+  SUMMARY_MODULE: new URL('../../../static/js/components/DownloadBatchSummaryModal.js', import.meta.url).pathname,
+  OTHER_MODELS_MODULE: new URL('../../../static/js/utils/otherModels.js', import.meta.url).pathname,
+}));
+
+vi.mock(MODAL_MANAGER_MODULE, () => ({
+  modalManager: { showModal: vi.fn(), closeModal: vi.fn() },
+}));
+vi.mock(UI_HELPERS_MODULE, () => ({
+  showToast: vi.fn(),
+  showActionToast: vi.fn(),
+  setupAutoNewlineOnPaste: vi.fn(),
+}));
+vi.mock(STATE_MODULE, () => ({
+  state: { global: { settings: {} }, loadingManager: {} },
+}));
+vi.mock(LOADING_MANAGER_MODULE, () => ({
+  LoadingManager: vi.fn(() => ({})),
+}));
+vi.mock(API_FACTORY_MODULE, () => ({
+  getModelApiClient: vi.fn(),
+  resetAndReload: vi.fn(),
+}));
+vi.mock(STORAGE_HELPERS_MODULE, () => ({
+  getStorageItem: vi.fn((_key, defaultValue) => defaultValue),
+  setStorageItem: vi.fn(),
+}));
+vi.mock(FOLDER_TREE_MANAGER_MODULE, () => ({
+  FolderTreeManager: vi.fn(() => ({})),
+}));
+vi.mock(I18N_HELPERS_MODULE, () => ({
+  translate: vi.fn((_key, _vars, fallback) => fallback ?? ''),
+}));
+vi.mock(SUMMARY_MODULE, () => ({
+  showDownloadBatchSummary: vi.fn(),
+}));
+vi.mock(OTHER_MODELS_MODULE, () => ({
+  enableOtherModels: vi.fn(),
+  openOtherModelsSettings: vi.fn(),
+}));
+
+const { DownloadManager } = await import(DOWNLOAD_MANAGER_MODULE);
+const { state } = await import(STATE_MODULE);
+const { setStorageItem } = await import(STORAGE_HELPERS_MODULE);
+
+describe('DownloadManager checkpoint/diffusion routing override', () => {
+  let manager;
+
+  function setupDom() {
+    document.body.innerHTML = `
+      <div id="routingOverrideGroup" style="display:none">
+        <button class="routing-override-option" data-routing="checkpoint"></button>
+        <button class="routing-override-option" data-routing="diffusion"></button>
+      </div>
+      <select id="modelRoot"></select>
+      <label id="modelRootLabel"></label>
+      <input id="folderPath" />
+      <input type="checkbox" id="useDefaultPath" />
+      <div id="manualPathSelection"></div>
+      <div id="targetPathDisplay"></div>
+    `;
+  }
+
+  function createManager(modelType, displayName = 'Model') {
+    manager = new DownloadManager();
+    manager.apiClient = {
+      modelType,
+      apiConfig: { config: { displayName } },
+      fetchModelRoots: vi.fn(),
+    };
+    manager.selectedFile = null;
+    manager.selectedFiles = [];
+    manager.currentVersion = null;
+    manager.initializeFolderTree = vi.fn().mockResolvedValue();
+    manager.folderTreeManager = { init: vi.fn(), getSelectedPath: vi.fn(() => '') };
+    manager.loadDefaultPathSetting = vi.fn();
+    vi.spyOn(manager, '_resolveOtherSubType').mockResolvedValue(null);
+  }
+
+  beforeEach(() => {
+    setupDom();
+    state.global.settings = {};
+    vi.clearAllMocks();
+  });
+
+  afterEach(() => {
+    vi.unstubAllGlobals();
+  });
+
+  it('shows the toggle for diffusion-routed checkpoints and marks diffusion active', async () => {
+    createManager('checkpoints', 'Checkpoint');
+    vi.spyOn(manager, '_resolveIsDiffusionModel').mockResolvedValue(true);
+    manager.apiClient.fetchModelRoots.mockResolvedValue({
+      success: true,
+      roots: ['/models/unet'],
+    });
+    state.global.settings.default_unet_root = '/models/unet';
+
+    await manager.proceedToLocationContent();
+
+    const group = document.getElementById('routingOverrideGroup');
+    expect(group.style.display).not.toBe('none');
+    const [checkpointBtn, diffusionBtn] = group.querySelectorAll('.routing-override-option');
+    expect(diffusionBtn.classList.contains('active')).toBe(true);
+    expect(diffusionBtn.getAttribute('aria-pressed')).toBe('true');
+    expect(checkpointBtn.classList.contains('active')).toBe(false);
+    expect(manager.apiClient.fetchModelRoots).toHaveBeenCalledWith('diffusion_model');
+    expect(document.getElementById('modelRoot').value).toBe('/models/unet');
+  });
+
+  it('keeps the toggle hidden on non-checkpoints pages', async () => {
+    createManager('loras', 'LoRA');
+    manager.apiClient.fetchModelRoots.mockResolvedValue({
+      success: true,
+      roots: ['/models/loras'],
+    });
+
+    await manager.proceedToLocationContent();
+
+    expect(document.getElementById('routingOverrideGroup').style.display).toBe('none');
+    expect(manager.apiClient.fetchModelRoots).toHaveBeenCalledWith();
+  });
+
+  it('re-fetches diffusion roots and preselects the unet default when overriding to diffusion', async () => {
+    createManager('checkpoints', 'Checkpoint');
+    vi.spyOn(manager, '_resolveIsDiffusionModel').mockResolvedValue(false);
+    manager.apiClient.fetchModelRoots
+      .mockResolvedValueOnce({ success: true, roots: ['/models/checkpoints'] })
+      .mockResolvedValueOnce({ success: true, roots: ['/models/unet'] });
+    state.global.settings.default_unet_root = '/models/unet';
+
+    await manager.proceedToLocationContent();
+    expect(document.getElementById('modelRoot').value).toBe('/models/checkpoints');
+
+    await manager.handleRoutingOverrideChange(true);
+
+    expect(manager.apiClient.fetchModelRoots).toHaveBeenLastCalledWith('diffusion_model');
+    const modelRoot = document.getElementById('modelRoot');
+    expect(Array.from(modelRoot.options).map(o => o.value)).toEqual(['/models/unet']);
+    expect(modelRoot.value).toBe('/models/unet');
+    const group = document.getElementById('routingOverrideGroup');
+    const [checkpointBtn, diffusionBtn] = group.querySelectorAll('.routing-override-option');
+    expect(checkpointBtn.classList.contains('active')).toBe(false);
+    expect(diffusionBtn.classList.contains('active')).toBe(true);
+  });
+
+  it('turns off Use Default Path for the session without persisting when overriding', async () => {
+    createManager('checkpoints', 'Checkpoint');
+    vi.spyOn(manager, '_resolveIsDiffusionModel').mockResolvedValue(false);
+    manager.apiClient.fetchModelRoots.mockResolvedValue({
+      success: true,
+      roots: ['/models/checkpoints'],
+    });
+
+    await manager.proceedToLocationContent();
+
+    manager.useDefaultPath = true;
+    document.getElementById('useDefaultPath').checked = true;
+
+    await manager.handleRoutingOverrideChange(true);
+
+    expect(manager.useDefaultPath).toBe(false);
+    expect(document.getElementById('useDefaultPath').checked).toBe(false);
+    expect(setStorageItem).not.toHaveBeenCalled();
+  });
+
+  it('clears the override when switching back to the auto-classified side', async () => {
+    createManager('checkpoints', 'Checkpoint');
+    vi.spyOn(manager, '_resolveIsDiffusionModel').mockResolvedValue(false);
+    manager.apiClient.fetchModelRoots.mockResolvedValue({
+      success: true,
+      roots: ['/models/checkpoints'],
+    });
+
+    await manager.proceedToLocationContent();
+    await manager.handleRoutingOverrideChange(true);
+    expect(manager._routingOverride).toBe(true);
+
+    manager.apiClient.fetchModelRoots.mockClear();
+    await manager.handleRoutingOverrideChange(false);
+
+    expect(manager._routingOverride).toBeNull();
+    // Back on the checkpoint group: no routing argument
+    expect(manager.apiClient.fetchModelRoots).toHaveBeenCalledWith();
+  });
+});