diff --git a/app/slm/dashboard.py b/app/slm/dashboard.py
index 07bf1eb..445b57d 100644
--- a/app/slm/dashboard.py
+++ b/app/slm/dashboard.py
@@ -139,53 +139,92 @@ async def get_live_view(unit_id: str, request: Request, slm_db: Session = Depend
     )
 
 
-@router.get("/config/{unit_id}")
-async def get_unit_config(unit_id: str, db: Session = Depends(get_slm_db)):
-    """Get configuration for a specific unit."""
-    config = db.query(NL43Config).filter_by(unit_id=unit_id).first()
-    if not config:
+@router.get("/config/{unit_id}", response_class=HTMLResponse)
+async def get_unit_config(unit_id: str, request: Request, roster_db: Session = Depends(get_seismo_db)):
+    """Return the HTML config form for a specific unit."""
+    unit = roster_db.query(RosterUnit).filter_by(
+        id=unit_id,
+        device_type="sound_level_meter"
+    ).first()
+
+    if not unit:
         raise HTTPException(status_code=404, detail="Unit configuration not found")
 
-    return {
-        "unit_id": config.unit_id,
-        "host": config.host,
-        "tcp_port": config.tcp_port,
-        "tcp_enabled": config.tcp_enabled,
-        "ftp_enabled": config.ftp_enabled,
-        "ftp_username": config.ftp_username,
-        "ftp_password": config.ftp_password,
-        "web_enabled": config.web_enabled,
-    }
+    return templates.TemplateResponse(
+        "partials/slm_config_form.html",
+        {
+            "request": request,
+            "unit": unit
+        }
+    )
 
 
 @router.post("/config/{unit_id}")
-async def update_unit_config(unit_id: str, config_data: Dict[str, Any], db: Session = Depends(get_slm_db)):
-    """Update configuration for a specific unit."""
-    config = db.query(NL43Config).filter_by(unit_id=unit_id).first()
+async def update_unit_config(
+    unit_id: str,
+    request: Request,
+    roster_db: Session = Depends(get_seismo_db),
+    slm_db: Session = Depends(get_slm_db)
+):
+    """Update configuration for a specific unit from the form submission."""
+    unit = roster_db.query(RosterUnit).filter_by(
+        id=unit_id,
+        device_type="sound_level_meter"
+    ).first()
 
+    if not unit:
+        raise HTTPException(status_code=404, detail="Unit configuration not found")
+
+    form = await request.form()
+
+    def get_int(value, default=None):
+        try:
+            return int(value) if value not in (None, "") else default
+        except (TypeError, ValueError):
+            return default
+
+    # Update roster fields
+    unit.slm_model = form.get("slm_model") or unit.slm_model
+    unit.slm_serial_number = form.get("slm_serial_number") or unit.slm_serial_number
+    unit.slm_frequency_weighting = form.get("slm_frequency_weighting") or unit.slm_frequency_weighting
+    unit.slm_time_weighting = form.get("slm_time_weighting") or unit.slm_time_weighting
+    unit.slm_measurement_range = form.get("slm_measurement_range") or unit.slm_measurement_range
+
+    unit.slm_host = form.get("slm_host") or None
+    unit.slm_tcp_port = get_int(form.get("slm_tcp_port"), unit.slm_tcp_port or 2255)
+    unit.slm_ftp_port = get_int(form.get("slm_ftp_port"), unit.slm_ftp_port or 21)
+
+    deployed_with_modem_id = form.get("deployed_with_modem_id") or None
+    unit.deployed_with_modem_id = deployed_with_modem_id
+
+    roster_db.commit()
+    roster_db.refresh(unit)
+
+    # Update or create NL43 config so SLMM can reach the device
+    config = slm_db.query(NL43Config).filter_by(unit_id=unit_id).first()
     if not config:
-        # Create new config
         config = NL43Config(unit_id=unit_id)
-        db.add(config)
+        slm_db.add(config)
 
-    # Update fields
-    if "host" in config_data:
-        config.host = config_data["host"]
-    if "tcp_port" in config_data:
-        config.tcp_port = config_data["tcp_port"]
-    if "tcp_enabled" in config_data:
-        config.tcp_enabled = config_data["tcp_enabled"]
-    if "ftp_enabled" in config_data:
-        config.ftp_enabled = config_data["ftp_enabled"]
-    if "ftp_username" in config_data:
-        config.ftp_username = config_data["ftp_username"]
-    if "ftp_password" in config_data:
-        config.ftp_password = config_data["ftp_password"]
-    if "web_enabled" in config_data:
-        config.web_enabled = config_data["web_enabled"]
+    # Resolve host from modem if present, otherwise fall back to direct IP or existing config
+    host_for_config = None
+    if deployed_with_modem_id:
+        modem = roster_db.query(RosterUnit).filter_by(
+            id=deployed_with_modem_id,
+            device_type="modem"
+        ).first()
+        if modem and modem.ip_address:
+            host_for_config = modem.ip_address
+    if not host_for_config:
+        host_for_config = unit.slm_host or config.host or "127.0.0.1"
 
-    db.commit()
-    db.refresh(config)
+    config.host = host_for_config
+    config.tcp_port = get_int(form.get("slm_tcp_port"), config.tcp_port or 2255)
+    config.tcp_enabled = True
+    config.ftp_enabled = bool(config.ftp_username and config.ftp_password)
+
+    slm_db.commit()
+    slm_db.refresh(config)
 
     return {"success": True, "unit_id": unit_id}
 
diff --git a/app/ui/templates/partials/slm_live_view.html b/app/ui/templates/partials/slm_live_view.html
index 54e2560..61115d0 100644
--- a/app/ui/templates/partials/slm_live_view.html
+++ b/app/ui/templates/partials/slm_live_view.html
@@ -568,9 +568,13 @@ function initLiveDataStream(unitId) {
         if (stopBtn) stopBtn.style.display = 'flex';
     };
 
-    window.currentWebSocket.onmessage = function(event) {
+    window.currentWebSocket.onmessage = async function(event) {
         try {
-            const data = JSON.parse(event.data);
+            let payload = event.data;
+            if (payload instanceof Blob) {
+                payload = await payload.text();
+            }
+            const data = typeof payload === 'string' ? JSON.parse(payload) : payload;
             console.log('WebSocket data received:', data);
             updateLiveMetrics(data);
             updateLiveChart(data);
diff --git a/app/ui/templates/sound_level_meters.html b/app/ui/templates/sound_level_meters.html
index 0e48b7d..9269ead 100644
--- a/app/ui/templates/sound_level_meters.html
+++ b/app/ui/templates/sound_level_meters.html
@@ -167,10 +167,18 @@ function initLiveDataStream(unitId) {
         if (stopBtn) stopBtn.style.display = 'flex';
     };
 
-    currentWebSocket.onmessage = function(event) {
-        const data = JSON.parse(event.data);
-        updateLiveChart(data);
-        updateLiveMetrics(data);
+    currentWebSocket.onmessage = async function(event) {
+        try {
+            let payload = event.data;
+            if (payload instanceof Blob) {
+                payload = await payload.text();
+            }
+            const data = typeof payload === 'string' ? JSON.parse(payload) : payload;
+            updateLiveChart(data);
+            updateLiveMetrics(data);
+        } catch (error) {
+            console.error('Error parsing WebSocket message:', error);
+        }
     };
 
     currentWebSocket.onerror = function(error) {