diff --git a/app/src/main/java/com/example/medilightv2android/managers/GreenZoneConstants.kt b/app/src/main/java/com/example/medilightv2android/managers/GreenZoneConstants.kt
index e5376eb..282ea23 100644
--- a/app/src/main/java/com/example/medilightv2android/managers/GreenZoneConstants.kt
+++ b/app/src/main/java/com/example/medilightv2android/managers/GreenZoneConstants.kt
@@ -41,6 +41,17 @@ object GreenZoneConstants {
 
     @Volatile var detectionMethod: DetectionMethod = DetectionMethod.METHOD_C
     @Volatile var bvMethod: BvMethod = BvMethod.V41
+
+    /**
+     * lr_ratio 강제 override (algorithm 팀 최신 표준: piezophantomtest 4830e7c).
+     *   - null      : computed (기존 Python `compute_lr_ratio` 알고리즘)
+     *   - Double    : 강제 값 (algorithm 팀 default = 1.0)
+     *
+     * Phantom 실측 검증: computed lr=0.68 → BV -38%. lr=1.0 fixed → -1.6% (APP 일치).
+     * 6채널 hardware LR 분해능 한계로 computed lr 신뢰도 낮음. Dev toggle 전환 가능.
+     */
+    @Volatile var lrRatioOverride: Double? = 1.0
+
     @Volatile var placementGuideMode: PlacementGuideMode = PlacementGuideMode.SIMPLE
     @Volatile var alignmentAlgo: AlignmentAlgo = AlignmentAlgo.V1   // default V1 (일반 사용자). V2 (Method D) 는 clinical alignment session 전용.
 
diff --git a/app/src/main/java/com/example/medilightv2android/managers/PiezoBVEstimator.kt b/app/src/main/java/com/example/medilightv2android/managers/PiezoBVEstimator.kt
index 3c173ac..9bc385d 100644
--- a/app/src/main/java/com/example/medilightv2android/managers/PiezoBVEstimator.kt
+++ b/app/src/main/java/com/example/medilightv2android/managers/PiezoBVEstimator.kt
@@ -398,7 +398,10 @@ fun estimateBladderVolume6ch(
     var centerWalls = PiezoHW.centerCh.map { if (it < allWalls.size) allWalls[it] else null }
     centerWalls = repairCenterWallsFor6ch(centerWalls)
     val lateralWalls = PiezoHW.lateralCh.map { if (it < allWalls.size) allWalls[it] else null }
-    val lrRatio = computeLrRatio(centerWalls, lateralWalls, sensorZMm = PiezoHW.sensorZMmAll)
+    // 2026-07-01: algorithm 팀 최신 표준 (piezophantomtest 4830e7c) — lr_ratio_override=1.0
+    //   Phantom 검증: computed lr 은 6채널 HW 한계로 -38% 오차. Dev panel 로 전환 가능.
+    val lrRatio = com.example.medilightv2android.managers.GreenZoneConstants.lrRatioOverride
+        ?: computeLrRatio(centerWalls, lateralWalls, sensorZMm = PiezoHW.sensorZMmAll)
     return estimateBladderVolume(
         walls = centerWalls,
         lrRatio = lrRatio,
diff --git a/app/src/main/java/com/example/medilightv2android/ui/views/monitoring/PiezoMonitoringView.kt b/app/src/main/java/com/example/medilightv2android/ui/views/monitoring/PiezoMonitoringView.kt
index ee32b4d..3f637d2 100644
--- a/app/src/main/java/com/example/medilightv2android/ui/views/monitoring/PiezoMonitoringView.kt
+++ b/app/src/main/java/com/example/medilightv2android/ui/views/monitoring/PiezoMonitoringView.kt
@@ -1905,6 +1905,24 @@ fun PiezoMonitoringView(appState: AppState) {
 
                         HorizontalDivider(modifier = Modifier.padding(vertical = dividerPadding))
 
+                        // 2026-07-01: lr_ratio override (algorithm 팀 4830e7c 표준)
+                        var lrFixed by remember {
+                            mutableStateOf(com.example.medilightv2android.managers.GreenZoneConstants.lrRatioOverride != null)
+                        }
+                        Row(modifier = Modifier.fillMaxWidth(), verticalAlignment = Alignment.CenterVertically) {
+                            Text("lr=1.0 fixed", fontSize = labelSize, fontWeight = FontWeight.SemiBold)
+                            Spacer(modifier = Modifier.weight(1f))
+                            Switch(checked = lrFixed,
+                                onCheckedChange = {
+                                    lrFixed = it
+                                    com.example.medilightv2android.managers.GreenZoneConstants.lrRatioOverride =
+                                        if (it) 1.0 else null
+                                },
+                                colors = SwitchDefaults.colors(checkedTrackColor = MlPrimary))
+                        }
+
+                        HorizontalDivider(modifier = Modifier.padding(vertical = dividerPadding))
+
                         // SG Filter
                         var sgEnabled by remember { mutableStateOf(analyzer.useSgFilter) }
                         Row(modifier = Modifier.fillMaxWidth(), verticalAlignment = Alignment.CenterVertically) {