diff --git a/VERSION b/VERSION
index bd8bf88..943f9cb 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-1.7.0
+1.7.1
diff --git a/changelog.json b/changelog.json
index 33de873..b689a93 100644
--- a/changelog.json
+++ b/changelog.json
@@ -1,5 +1,22 @@
 {
   "versions": [
+    {
+      "version": "1.7.1",
+      "date": "2026-05-12",
+      "changes": {
+        "features": [],
+        "improvements": [
+          "Loop SARA: detection SIM injoignable avant escalade hardware reboot (evite les reboots inutiles en boucle quand la SIM est absente/mal inseree)",
+          "Logs HTML: bloc rouge tres visible quand la SIM n'est pas detectee (bordure, fond rose, message d'action clair)",
+          "Notification WiFi dediee: 'SIM NOT DETECTED -> physical check required' au lieu du generique 'UDP socket creation failed'"
+        ],
+        "fixes": [
+          "Plus de hardware reboots repetes a chaque cycle de 60s quand la SIM est physiquement injoignable (economie courant + usure transistor GPIO 16)"
+        ],
+        "compatibility": []
+      },
+      "notes": "Quand la sequence PDP echoue, le script verifie maintenant AT+CPIN? et AT+CCID pour diagnostiquer si le probleme vient de la SIM ou du reseau. Si SIM absente: notification claire + arret propre, pas de reboot. Si SIM presente: comportement actuel (reboot hardware). Le check ne s'execute qu'en cas d'erreur, zero impact sur le happy path."
+    },
     {
       "version": "1.7.0",
       "date": "2026-04-27",
diff --git a/loop/SARA_send_data_v2.py b/loop/SARA_send_data_v2.py
index 9bc1b53..57872fc 100755
--- a/loop/SARA_send_data_v2.py
+++ b/loop/SARA_send_data_v2.py
@@ -620,6 +620,35 @@ def reset_PSD_CSD_connection():
 
     return pdp_reset_success
 
+def check_sim_status():
+    """
+    Quick SIM presence check using AT+CPIN? and AT+CCID.
+    Called only when something has already gone wrong (eg. PDP reset failed),
+    to distinguish a SIM problem from a network/PDP problem.
+        returns True if SIM is detected and READY, False otherwise.
+    """
+    print("➡️ Checking SIM status (AT+CPIN? and AT+CCID)")
+
+    # 1. CPIN -> doit retourner READY
+    ser_sara.reset_input_buffer()
+    ser_sara.write(b'AT+CPIN?\r')
+    response_cpin = read_complete_response(ser_sara, wait_for_lines=["OK", "+CME ERROR", "ERROR"], debug=False)
+    print('<p class="text-danger-emphasis">', end="")
+    print(response_cpin)
+    print("</p>", end="")
+    cpin_ok = response_cpin is not None and "READY" in response_cpin
+
+    # 2. CCID -> doit retourner l'ICCID
+    ser_sara.reset_input_buffer()
+    ser_sara.write(b'AT+CCID\r')
+    response_ccid = read_complete_response(ser_sara, wait_for_lines=["OK", "+CME ERROR", "ERROR"], debug=False)
+    print('<p class="text-danger-emphasis">', end="")
+    print(response_ccid)
+    print("</p>", end="")
+    ccid_ok = response_ccid is not None and "+CCID" in response_ccid and "ERROR" not in response_ccid
+
+    return cpin_ok and ccid_ok
+
 def reset_server_hostname(profile_id):
     """
     Function that reset server hostname (URL) connection for the SARA R5
@@ -1208,6 +1237,34 @@ try:
                 print(response_SARA_1)
             else:
                 print("⛔There were issues with the modem CSD PSD reinitialize process")
+
+                # Diagnostic : SIM injoignable OU problème réseau/PDP ?
+                sim_ok = check_sim_status()
+
+                if not sim_ok:
+                    # SIM injoignable -> un reboot hardware ne résoudra rien
+                    print('<hr>')
+                    print('<div style="border: 3px solid red; background-color: #ffe5e5; padding: 10px; margin: 10px 0;">')
+                    print('<span style="color: red;font-weight: bold;font-size: 1.4em;">🚨🚨🚨 SIM CARD NOT DETECTED 🚨🚨🚨</span><br>')
+                    print('<span style="color: red;font-weight: bold;">⛔ Le modem ne parvient pas à lire la carte SIM.</span><br>')
+                    print('<span style="color: red;font-weight: bold;">⛔ AT+CPIN? et AT+CCID ont tous les deux échoué.</span><br>')
+                    print('<span style="color: red;font-weight: bold;">👉 Action requise : vérifier physiquement la carte SIM (sortir/réinsérer, nettoyer les contacts).</span><br>')
+                    print('<span style="color: red;font-weight: bold;">👉 Pas de hardware reboot — inutile dans ce cas, économise courant et usure.</span>')
+                    print('</div>')
+                    print('<hr>')
+
+                    # LED rouge clignotante
+                    led_thread = Thread(target=blink_led, args=(24, 5, 0.5))
+                    led_thread.start()
+
+                    # Notification WIFI explicite
+                    send_error_notification(device_id, "SIM NOT DETECTED -> physical check required (no hardware reboot)")
+
+                    # end loop, pas d'escalade
+                    sys.exit()
+
+                # SIM OK -> c'est un problème réseau/PDP, escalade hardware reboot comme avant
+                print('<span style="color: green;font-weight: bold;">✅ SIM card detected — issue is network/PDP related</span>')
                 print("🔄 PDP reset failed → escalating to hardware reboot")
                 # Clignotement LED rouge en cas d'erreur
                 led_thread = Thread(target=blink_led, args=(24, 5, 0.5))