diff --git a/app/routes/api.py b/app/routes/api.py
index 0ee177e..8237f0d 100644
--- a/app/routes/api.py
+++ b/app/routes/api.py
@@ -1170,6 +1170,14 @@ def get_device_config():
         if not info:
             return jsonify({'success': False, 'error': 'No device info available'}), 503
 
+        path_hash_mode = None
+        try:
+            phm_result = dm.get_param('path_hash_mode')
+            if phm_result.get('success'):
+                path_hash_mode = phm_result.get('data', {}).get('path_hash_mode')
+        except Exception as e:
+            logger.warning(f"Could not read path_hash_mode: {e}")
+
         return jsonify({
             'success': True,
             'config': {
@@ -1177,6 +1185,7 @@ def get_device_config():
                 'lat': info.get('adv_lat', 0),
                 'lon': info.get('adv_lon', 0),
                 'advert_loc_policy': info.get('adv_loc_policy', 0),
+                'path_hash_mode': path_hash_mode,
                 'radio_freq': info.get('radio_freq', 0),
                 'radio_bw': info.get('radio_bw', 0),
                 'radio_sf': info.get('radio_sf', 0),
@@ -1224,6 +1233,19 @@ def update_device_config():
             if not result.get('success'):
                 errors.append(f"advert_loc_policy: {result.get('error')}")
 
+        # Path hash mode (0=1B, 1=2B, 2=3B)
+        if 'path_hash_mode' in data and data['path_hash_mode'] is not None:
+            try:
+                phm = int(data['path_hash_mode'])
+                if phm not in (0, 1, 2):
+                    errors.append(f"path_hash_mode: must be 0, 1, or 2")
+                else:
+                    result = dm.set_param('path_hash_mode', str(phm))
+                    if not result.get('success'):
+                        errors.append(f"path_hash_mode: {result.get('error')}")
+            except (TypeError, ValueError):
+                errors.append("path_hash_mode: invalid value")
+
         # Radio params (all 4 together)
         if 'radio_freq' in data:
             freq = float(data['radio_freq'])
diff --git a/app/static/js/app.js b/app/static/js/app.js
index 02bef85..b18bdd9 100644
--- a/app/static/js/app.js
+++ b/app/static/js/app.js
@@ -1872,6 +1872,13 @@ async function loadDeviceConfig() {
         document.getElementById('settDeviceLat').value = c.lat || '';
         document.getElementById('settDeviceLon').value = c.lon || '';
         document.getElementById('settDeviceAdvertLoc').checked = !!c.advert_loc_policy;
+        const phmSel = document.getElementById('settDevicePathHashMode');
+        if (phmSel) {
+            const phm = (c.path_hash_mode === 0 || c.path_hash_mode === 1 || c.path_hash_mode === 2)
+                ? String(c.path_hash_mode) : '0';
+            phmSel.value = phm;
+            phmSel.dataset.initial = phm;
+        }
 
         // Radio
         document.getElementById('settRadioFreq').value = c.radio_freq || '';
@@ -1910,21 +1917,28 @@ async function saveDevicePublicInfo() {
     const lon = parseFloat(document.getElementById('settDeviceLon').value) || 0;
     const advertLoc = document.getElementById('settDeviceAdvertLoc').checked;
 
+    const phmSel = document.getElementById('settDevicePathHashMode');
+    const payload = {
+        name: name,
+        lat: lat,
+        lon: lon,
+        advert_loc_policy: advertLoc
+    };
+    if (phmSel && phmSel.value !== phmSel.dataset.initial) {
+        payload.path_hash_mode = parseInt(phmSel.value, 10);
+    }
+
     try {
         const resp = await fetch('/api/device/config', {
             method: 'POST',
             headers: { 'Content-Type': 'application/json' },
-            body: JSON.stringify({
-                name: name,
-                lat: lat,
-                lon: lon,
-                advert_loc_policy: advertLoc
-            })
+            body: JSON.stringify(payload)
         });
         const data = await resp.json();
         if (data.success) {
             showNotification('Public info saved', 'success');
             _selfInfo = null;
+            if (phmSel) phmSel.dataset.initial = phmSel.value;
         } else {
             showNotification(data.error || 'Failed to save', 'danger');
         }
diff --git a/app/templates/base.html b/app/templates/base.html
index ae76df8..08be202 100644
--- a/app/templates/base.html
+++ b/app/templates/base.html
@@ -440,6 +440,19 @@
                                                         </div>
                                                     </td>
                                                 </tr>
+                                                <tr>
+                                                    <td class="ps-0">Path hash mode
+                                                        <span class="badge rounded-pill text-muted" data-bs-toggle="tooltip"
+                                                            title="Bytes per hop in routing paths. 1B = shortest path, more collisions; 3B = longest, fewest collisions."><i class="bi bi-info-circle"></i></span>
+                                                    </td>
+                                                    <td class="pe-0">
+                                                        <select class="form-select form-select-sm" id="settDevicePathHashMode">
+                                                            <option value="0">1 byte (default)</option>
+                                                            <option value="1">2 bytes</option>
+                                                            <option value="2">3 bytes</option>
+                                                        </select>
+                                                    </td>
+                                                </tr>
                                             </tbody>
                                         </table>
                                         <div class="d-flex gap-2">
@@ -723,6 +736,9 @@
                         </div>
                     </div>
                 </div>
+                <div class="modal-footer py-2">
+                    <button type="button" class="btn btn-secondary btn-sm" data-bs-dismiss="modal">Close</button>
+                </div>
             </div>
         </div>
     </div>