diff --git a/containers/libreportal/frontend/css/backup.css b/containers/libreportal/frontend/css/backup.css
index f3aab44..ede4a82 100755
--- a/containers/libreportal/frontend/css/backup.css
+++ b/containers/libreportal/frontend/css/backup.css
@@ -723,6 +723,47 @@
     border-top: 1px dashed rgba(var(--text-rgb), 0.08);
 }
 
+/* Full-width "Advanced" disclosure in the location editor's Connection
+   section. Reveals the advanced fields (URI override, SSH port, append-only). */
+.backup-loc-advanced-toggle {
+    display: flex;
+    align-items: center;
+    gap: 8px;
+    width: 100%;
+    margin-top: 14px;
+    padding: 10px 12px;
+    background: rgba(var(--text-rgb), 0.03);
+    border: 1px solid rgba(var(--text-rgb), 0.08);
+    border-radius: 8px;
+    color: var(--text-primary);
+    font: inherit;
+    font-size: 0.9rem;
+    font-weight: 600;
+    cursor: pointer;
+    transition: background 0.15s ease;
+}
+
+.backup-loc-advanced-toggle:hover {
+    background: rgba(var(--text-rgb), 0.06);
+}
+
+.backup-loc-advanced-chevron {
+    transition: transform 0.15s ease;
+    flex-shrink: 0;
+}
+
+.backup-loc-advanced-toggle.open .backup-loc-advanced-chevron {
+    transform: rotate(90deg);
+}
+
+.backup-loc-advanced {
+    margin-top: 12px;
+}
+
+.backup-loc-advanced[hidden] {
+    display: none;
+}
+
 .backup-form-footer {
     display: flex;
     justify-content: flex-end;
diff --git a/containers/libreportal/frontend/js/components/backup/backup-page.js b/containers/libreportal/frontend/js/components/backup/backup-page.js
index ec586c5..816f003 100644
--- a/containers/libreportal/frontend/js/components/backup/backup-page.js
+++ b/containers/libreportal/frontend/js/components/backup/backup-page.js
@@ -198,6 +198,18 @@ class BackupPage {
                 return;
             }
 
+            const advToggle = e.target.closest('[data-action="toggle-loc-advanced"]');
+            if (advToggle) {
+                const sec = document.getElementById(advToggle.dataset.target);
+                if (sec) {
+                    const show = sec.hasAttribute('hidden');
+                    sec.toggleAttribute('hidden', !show);
+                    advToggle.setAttribute('aria-expanded', show ? 'true' : 'false');
+                    advToggle.classList.toggle('open', show);
+                }
+                return;
+            }
+
             if (e.target.closest('[data-close-modal]') || e.target.matches('.backup-modal')) {
                 this.closeAllModals();
                 return;
@@ -263,7 +275,8 @@ class BackupPage {
         const ts = Date.now();
         const [dashboard, locations] = await Promise.all([
             this.fetchJson(`/data/backup/generated/dashboard.json?t=${ts}`),
-            this.fetchJson(`/data/backup/generated/locations.json?t=${ts}`)
+            this.fetchJson(`/data/backup/generated/locations.json?t=${ts}`),
+            this.loadSystemConfigs()
         ]);
         this.dashboard = dashboard;
         this.locations = locations;
@@ -285,6 +298,19 @@ class BackupPage {
         catch { return null; }
     }
 
+    /* Load the unified config file once for the Locations editor: configData
+       carries field metadata (titles/descriptions/options/advanced) the editor
+       renders from; systemConfigs is the flat key->value map used for default
+       lookups (e.g. CFG_BACKUP_ENGINE) and save-time change detection. */
+    async loadSystemConfigs() {
+        const data = await this.fetchJson(`/data/config/generated/configs.json?t=${Date.now()}`);
+        if (!data) return;
+        window.configData = data;
+        const flat = {};
+        for (const [k, v] of Object.entries(data.config || {})) flat[k] = v?.value ?? '';
+        window.systemConfigs = flat;
+    }
+
     async loadEngines() {
         const ts = Date.now();
         const index = await this.fetchJson(`/data/backup/generated/engines/index.json?t=${ts}`);
@@ -1400,19 +1426,61 @@ class BackupPage {
             KEEP_YEARLY: loc.keep_yearly
         };
 
-        // Single .config-fields grid, exactly like /config's renderer — the grid
-        // (repeat(3, 1fr)) handles the row layout itself, and hidden fields
-        // (PATH_MODE/SSH/etc.) drop out cleanly without leaving column gaps.
-        let html = '<div class="config-fields">';
-        for (const suffix of suffixes) {
-            const def = BACKUP_LOC_FIELD_DEFS[suffix];
-            if (!def) continue;
+        // Field metadata now comes from configs.json (window.configData): the
+        // generator emits CFG_BACKUP_LOC_N_* titles/descriptions plus an
+        // "advanced" flag. BACKUP_LOC_FIELD_DEFS stays only as a fallback for a
+        // sparse location.config that doesn't describe a field yet.
+        const advancedFallback = new Set(['URI', 'SSH_PORT', 'APPEND_ONLY']);
+        const fieldMeta = (suffix) => {
             const key = `CFG_BACKUP_LOC_${idx}_${suffix}`;
+            const cfg = window.configData?.config?.[key] || {};
+            const def = BACKUP_LOC_FIELD_DEFS[suffix] || {};
+            // Fallback set keeps these advanced even on legacy locations whose
+            // location.config predates the **ADVANCED** marker; configData can
+            // additionally flag others.
+            const advanced = advancedFallback.has(suffix) || cfg.advanced === true;
+            return {
+                key,
+                exists: !!(cfg.title || cfg.description || BACKUP_LOC_FIELD_DEFS[suffix]),
+                title: cfg.title || def.title || suffix,
+                description: cfg.description ?? def.description ?? '',
+                advanced
+            };
+        };
+
+        const renderField = (suffix) => {
+            const m = fieldMeta(suffix);
             const value = (locValueLookup[suffix] ?? '').toString();
-            const fieldId = `config-${key}`;
-            html += ConfigShared.generateField(fieldId, key, value, def.title, def.description, {}, {});
+            return ConfigShared.generateField(`config-${m.key}`, m.key, value, m.title, m.description, {}, {});
+        };
+
+        const basic = [];
+        const advanced = [];
+        for (const suffix of suffixes) {
+            const m = fieldMeta(suffix);
+            if (!m.exists) continue;
+            (m.advanced ? advanced : basic).push(suffix);
         }
+
+        // Basics stay in the .config-fields grid (same as /config). Advanced
+        // fields (URI override, SSH port, append-only) tuck behind a full-width
+        // disclosure so the common case opens simple.
+        let html = '<div class="config-fields">';
+        html += basic.map(renderField).join('');
         html += '</div>';
+
+        if (advanced.length) {
+            const secId = `backup-loc-${idx}-advanced`;
+            html += `
+                <button type="button" class="backup-loc-advanced-toggle" data-action="toggle-loc-advanced" data-target="${secId}" aria-expanded="false" aria-controls="${secId}">
+                    <svg class="backup-loc-advanced-chevron" width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><polyline points="9 18 15 12 9 6"></polyline></svg>
+                    <span>Advanced</span>
+                </button>
+                <div class="config-fields backup-loc-advanced" id="${secId}" hidden>
+                    ${advanced.map(renderField).join('')}
+                </div>
+            `;
+        }
         return html;
     }
 
@@ -1615,10 +1683,6 @@ class BackupPage {
     }
 
     async reloadAfterSave() {
-        try {
-            const r = await fetch(`/data/config/generated/configs.json?t=${Date.now()}`);
-            if (r.ok) window.systemConfigs = await r.json();
-        } catch {}
         await this.refreshAll();
         this.render();
     }