diff --git a/libs/BatterieNetzfahrplanV4RueckmeldungTrait.php b/libs/BatterieNetzfahrplanV4RueckmeldungTrait.php
index 0ddfcdd..d2fd5dc 100644
--- a/libs/BatterieNetzfahrplanV4RueckmeldungTrait.php
+++ b/libs/BatterieNetzfahrplanV4RueckmeldungTrait.php
@@ -49,7 +49,8 @@ trait BatterieNetzfahrplanV4RueckmeldungTrait
                     return false;
                 },
                 $reader,
-                static fn():int=>time()
+                static fn():int=>time(),
+                static function(int $microseconds):void { usleep($microseconds); }
             );
             $this->SetBuffer('V4ConfirmedFeedback',json_encode($result,JSON_THROW_ON_ERROR));
             return $result;
diff --git a/libs/ManagerNetzfahrplanV4EmpfangTrait.php b/libs/ManagerNetzfahrplanV4EmpfangTrait.php
index a6fde3f..0785d88 100644
--- a/libs/ManagerNetzfahrplanV4EmpfangTrait.php
+++ b/libs/ManagerNetzfahrplanV4EmpfangTrait.php
@@ -47,10 +47,10 @@ trait ManagerNetzfahrplanV4EmpfangTrait
     /** Appended dynamically; existing form.json and parallel portal GUI stay untouched. */
     private function netzfahrplanV4EmpfangFormular(): array
     {
-        return ['type' => 'ExpansionPanel', 'caption' => 'V4 Planempfang / Sollwert-Vorschau', 'items' => [
-            ['type' => 'Label', 'caption' => 'NUR BEOBACHTEN. Kein Lade-/Entladebefehl. Der alte intelligente Netzfahrplan muss AUS bleiben.'],
+        return ['type' => 'ExpansionPanel', 'caption' => 'V4 Planempfang / Prognosemanager', 'items' => [
+            ['type' => 'Label', 'caption' => 'Der alte intelligente Netzfahrplan muss AUS bleiben. Die separate Laufzeitvariable unter dem Manager schaltet den zeitlich begrenzten Testbetrieb ein oder aus.'],
             ['type' => 'CheckBox', 'name' => 'NetzfahrplanV4EmpfangAktiv', 'caption' => 'V4 Schattenplan empfangen und Sollwert anzeigen (keine Steuerung)'],
-            ['type' => 'Label', 'caption' => 'Diagnose und Sollwerte stehen in den beiden V4-Vorschauvariablen unterhalb des Managers.'],
+            ['type' => 'Label', 'caption' => 'Schalter: V4 Prognosemanager aktiv (Testbetrieb). Ausschalten beendet V4 und fordert sofort 0 W an. Maximale Laufzeit ab dem ersten Einschalten: 48 Stunden.'],
             ['type' => 'Button', 'caption' => 'Plan jetzt pruefen (Abruf begrenzt auf 1/min)',
                 'onClick' => "IPS_RequestAction(\$id, 'NetzfahrplanV4Empfangen', true);"],
         ]];
@@ -172,6 +172,10 @@ trait ManagerNetzfahrplanV4EmpfangTrait
                 if (is_string($configured) && !in_array(trim($configured),['','{}'],true)) {
                     if (count($topology)!==1) throw new RuntimeException('feedback_multi_asset_adapter_required');
                     $f=json_decode(ENELIX_GetV4BatterieRueckmeldung($controller),true,32,JSON_THROW_ON_ERROR);
+                    if (($f['status']??null)==='unavailable') {
+                        $reason=is_string($f['reason']??null)?$f['reason']:'unknown';
+                        throw new RuntimeException('feedback_unavailable:'.substr($reason,0,180));
+                    }
                     if (($f['installationId']??null)!==$this->ReadAttributeString('LizenzInstallationID')
                         || ($f['assetId']??null)!==$asset['ID'] || ($f['managerId']??null)!==$this->InstanceID
                         || ($f['batteryInstanceId']??null)!==$controller || !is_numeric($f['batteryW']??null)
diff --git a/libs/NetzfahrplanV4Geraeteabruf.php b/libs/NetzfahrplanV4Geraeteabruf.php
index 097943e..af58290 100644
--- a/libs/NetzfahrplanV4Geraeteabruf.php
+++ b/libs/NetzfahrplanV4Geraeteabruf.php
@@ -25,7 +25,8 @@ final class NetzfahrplanV4Geraeteabruf
         callable $moduleId,
         callable $refresh,
         callable $reader,
-        callable $clock
+        callable $clock,
+        ?callable $pause = null
     ): array {
         $config = NetzfahrplanV4Rueckmeldung::configuration($config);
         $groups = [];
@@ -43,7 +44,17 @@ final class NetzfahrplanV4Geraeteabruf
             if (!in_array($module, [self::MBUS_DEVICE, self::MODBUS_DEVICE, self::MODBUS_ADDRESS], true)) {
                 throw new InvalidArgumentException('feedback_refresh_module_unsupported:' . $sources[0]['key']);
             }
-            if ($refresh($parentId, $module) !== true) {
+            $confirmed = false;
+            for ($attempt = 1; $attempt <= 4; ++$attempt) {
+                if ($refresh($parentId, $module) === true) {
+                    $confirmed = true;
+                    break;
+                }
+                if ($attempt < 4 && $pause !== null) {
+                    $pause(200000);
+                }
+            }
+            if (!$confirmed) {
                 throw new InvalidArgumentException('feedback_device_read_failed:' . $sources[0]['key']);
             }
             $confirmedAt = $clock();
diff --git a/tests/V4Feedback/device_read_checks.php b/tests/V4Feedback/device_read_checks.php
index 6b00aca..bb6f455 100644
--- a/tests/V4Feedback/device_read_checks.php
+++ b/tests/V4Feedback/device_read_checks.php
@@ -35,6 +35,12 @@ dcheck($f['deviceReadConfirmed']===true&&$f['sourceOldestAt']===$n-1,'successful
 dcheck($f['sourceVariableOldestAt']===$n-100,'original VariableUpdated retained separately');
 dcheck($f['batteryW']===-3000.0&&$f['usableForTrial'],'unchanged values accepted after confirmed device response');
 
+[$c,$r,$n]=dfixture();$times=[$n,$n,$n];$attempts=0;$pauses=[];
+$f=D::snapshot($c,fn($id)=>D::MODBUS_DEVICE,
+ function()use(&$attempts){$attempts++;return $attempts>=2;},fn($id)=>$r[$id],
+ function()use(&$times){return array_shift($times);},function($us)use(&$pauses){$pauses[]=$us;});
+dcheck($attempts===3&&$pauses===[200000],'transient busy read is retried once without relaxing confirmation');
+
 [$c,$r,$n]=dfixture();$times=[$n,$n,$n];
 dfails(fn()=>D::snapshot($c,fn($id)=>D::MODBUS_DEVICE,fn()=>false,fn($id)=>$r[$id],function()use(&$times){return array_shift($times);}),
  'failed device read rejected');
diff --git a/tests/V4Feedback/receiver_checks.php b/tests/V4Feedback/receiver_checks.php
index f617f4b..62887d5 100644
--- a/tests/V4Feedback/receiver_checks.php
+++ b/tests/V4Feedback/receiver_checks.php
@@ -34,8 +34,9 @@ namespace {
  ck($p['status']==='preview_only'&&$p['actualBatteryW']==0,'real receiver uses corrected physical feedback rather than held -9kW');
  ck($p['previewBatteryW']==3000,'net target translated once to total battery demand');
  ck($p['canDispatch']===false&&$p['localFeedback']['b']['estimated']===true,'model feedback remains marked and preview grants no dispatch');
- $feedback=['status'=>'unavailable','batteryW'=>null,'gridW'=>null];$p=json_decode($m->GetNetzfahrplanV4Vorschau(),true);
+ $feedback=['status'=>'unavailable','reason'=>'feedback_device_read_failed:grid','batteryW'=>null,'gridW'=>null];$p=json_decode($m->GetNetzfahrplanV4Vorschau(),true);
  ck($p['status']==='unavailable'&&$p['previewBatteryW']===null,'configured feedback failure never falls back to held virtual display');
+ ck(str_contains($p['reason'],'feedback_unavailable:feedback_device_read_failed:grid'),'configured feedback exposes bounded root cause without credentials');
  $configured=false;$p=json_decode($m->GetNetzfahrplanV4Vorschau(),true);
  ck($p['status']==='preview_only'&&$p['feedbackMeaning']==='legacy_display_only_not_for_trial','unconfigured old preview stays compatible but explicitly not for control');
  ck($p['canDispatch']===false,'legacy display cannot gain actuation permission');