diff --git a/sniffer/decompile_kaiyu.ps1 b/sniffer/decompile_kaiyu.ps1
index d99c287..25d748f 100644
--- a/sniffer/decompile_kaiyu.ps1
+++ b/sniffer/decompile_kaiyu.ps1
@@ -2,6 +2,10 @@
 #
 # Run from D:\HereMyHope\hh-bt-controller:
 #   powershell -ExecutionPolicy Bypass -File sniffer/decompile_kaiyu.ps1
+#
+# Automatically picks jadx version based on your Java:
+#   Java 8  -> jadx 1.2.0 (last version supporting Java 8)
+#   Java 11+ -> jadx 1.5.0
 
 $BaseDir   = "D:\Claude\HH-BT-Controller\decompile"
 $JadxDir   = "$BaseDir\jadx"
@@ -17,39 +21,78 @@ Write-Host "============================================" -ForegroundColor Cyan
 Write-Host "  KAIYU APK Decompiler" -ForegroundColor Cyan
 Write-Host "============================================" -ForegroundColor Cyan
 
-# 1. Download jadx
-if (-not (Test-Path "$JadxDir\bin\jadx.bat")) {
-    Write-Host "`n[1/4] Downloading jadx 1.5.0..." -ForegroundColor Yellow
-    $url = "https://github.com/skylot/jadx/releases/download/v1.5.0/jadx-1.5.0.zip"
+# ── Detect Java version ───────────────────────────────────────────────────────
+Write-Host "`nDetecting Java version..." -ForegroundColor Gray
+$javaVer = 8
+try {
+    $javaOut = & java -version 2>&1 | Select-Object -First 1
+    Write-Host "  $javaOut" -ForegroundColor Gray
+    if ($javaOut -match '"(\d+)[\._]') {
+        $major = [int]$Matches[1]
+        # Java 8 reports as "1.8.x", Java 11+ reports as "11.x"
+        $javaVer = if ($major -eq 1) {
+            [int]($javaOut -replace '.*"1\.(\d+).*','$1')
+        } else { $major }
+    }
+} catch { Write-Host "  Could not detect Java version, assuming Java 8" -ForegroundColor Yellow }
+
+Write-Host "  Java major version: $javaVer" -ForegroundColor Gray
+
+# Pick jadx version accordingly
+if ($javaVer -ge 11) {
+    $jadxVersion = "1.5.0"
+    $jadxUrl = "https://github.com/skylot/jadx/releases/download/v1.5.0/jadx-1.5.0.zip"
+    Write-Host "  Using jadx 1.5.0 (Java 11+ detected)" -ForegroundColor Gray
+} else {
+    $jadxVersion = "1.2.0"
+    $jadxUrl = "https://github.com/skylot/jadx/releases/download/v1.2.0/jadx-1.2.0.zip"
+    Write-Host "  Using jadx 1.2.0 (Java 8 detected - last version supporting Java 8)" -ForegroundColor Yellow
+}
+
+# ── 1. Download jadx ──────────────────────────────────────────────────────────
+$jadxBat = Get-ChildItem -Path $JadxDir -Recurse -Filter "jadx.bat" -ErrorAction SilentlyContinue |
+           Select-Object -First 1 -ExpandProperty FullName
+
+if (-not $jadxBat) {
+    Write-Host "`n[1/4] Downloading jadx $jadxVersion..." -ForegroundColor Yellow
     try {
-        Invoke-WebRequest -Uri $url -OutFile $JadxZip -UseBasicParsing
-        Write-Host "      Downloaded ($([math]::Round((Get-Item $JadxZip).Length/1MB,1)) MB)"
+        Invoke-WebRequest -Uri $jadxUrl -OutFile $JadxZip -UseBasicParsing
+        $sizeMB = [math]::Round((Get-Item $JadxZip).Length / 1MB, 1)
+        Write-Host "      Downloaded ($sizeMB MB)"
+        Write-Host "      Extracting..."
         Expand-Archive -Path $JadxZip -DestinationPath $JadxDir -Force
         Remove-Item $JadxZip -Force
-        Write-Host "      jadx ready." -ForegroundColor Green
+        $jadxBat = Get-ChildItem -Path $JadxDir -Recurse -Filter "jadx.bat" |
+                   Select-Object -First 1 -ExpandProperty FullName
+        Write-Host "      jadx ready: $jadxBat" -ForegroundColor Green
     } catch {
         Write-Host "[ERROR] Download failed: $_" -ForegroundColor Red
-        Write-Host "  Download manually: $url"
-        Write-Host "  Extract to: $JadxDir  then re-run."
+        Write-Host "  Download manually: $jadxUrl"
+        Write-Host "  Extract to: $JadxDir"
         Read-Host; exit 1
     }
 } else {
-    Write-Host "`n[1/4] jadx already present." -ForegroundColor Green
+    Write-Host "`n[1/4] jadx already present: $jadxBat" -ForegroundColor Green
 }
 
-# 2. Pull APK
+if (-not $jadxBat) {
+    Write-Host "[ERROR] jadx.bat not found after extraction." -ForegroundColor Red
+    Read-Host; exit 1
+}
+
+# ── 2. Pull APK ───────────────────────────────────────────────────────────────
 if (-not (Test-Path $ApkPath) -or (Get-Item $ApkPath).Length -lt 1MB) {
     Write-Host "`n[2/4] Pulling APK from phone..." -ForegroundColor Yellow
     $pmOut = & $Adb shell "pm path $Pkg" 2>&1
     if ($pmOut -notmatch "package:") {
-        Write-Host "[ERROR] KAIYU not found on device. Is phone connected?" -ForegroundColor Red
+        Write-Host "[ERROR] KAIYU not found on device." -ForegroundColor Red
         & $Adb devices; Read-Host; exit 1
     }
     $apkOnDevice = ($pmOut -split "`n" | Where-Object { $_ -match "package:" } |
-                    Select-Object -First 1).Replace("package:","").Trim()
+                    Select-Object -First 1).Replace("package:", "").Trim()
     Write-Host "      Device path: $apkOnDevice"
     & $Adb pull $apkOnDevice $ApkPath
-    if (-not (Test-Path $ApkPath)) {
+    if (-not (Test-Path $ApkPath) -or (Get-Item $ApkPath).Length -lt 1MB) {
         & $Adb shell "cp '$apkOnDevice' /sdcard/kaiyu_tmp.apk"
         & $Adb pull /sdcard/kaiyu_tmp.apk $ApkPath
         & $Adb shell "rm /sdcard/kaiyu_tmp.apk" 2>&1 | Out-Null
@@ -59,25 +102,28 @@ if (-not (Test-Path $ApkPath) -or (Get-Item $ApkPath).Length -lt 1MB) {
     }
     Write-Host "      APK: $([math]::Round((Get-Item $ApkPath).Length/1MB,1)) MB" -ForegroundColor Green
 } else {
-    Write-Host "`n[2/4] APK already pulled ($([math]::Round((Get-Item $ApkPath).Length/1MB,1)) MB)." -ForegroundColor Green
+    Write-Host "`n[2/4] APK already pulled ($([math]::Round((Get-Item $ApkPath).Length/1MB,1)) MB) -- skipping." -ForegroundColor Green
 }
 
-# 3. Decompile
-Write-Host "`n[3/4] Decompiling with jadx (1-3 min)..." -ForegroundColor Yellow
-$jadxBat = Get-ChildItem -Path $JadxDir -Recurse -Filter "jadx.bat" |
-           Select-Object -First 1 -ExpandProperty FullName
-if (-not $jadxBat) {
-    Write-Host "[ERROR] jadx.bat not found in $JadxDir" -ForegroundColor Red; Read-Host; exit 1
+# ── 3. Decompile ──────────────────────────────────────────────────────────────
+Write-Host "`n[3/4] Decompiling with jadx $jadxVersion (1-3 min)..." -ForegroundColor Yellow
+if (Test-Path $OutputDir) {
+    Write-Host "      Removing previous output..."
+    Remove-Item -Recurse -Force $OutputDir
 }
-if (Test-Path $OutputDir) { Remove-Item -Recurse -Force $OutputDir }
 
 & $jadxBat --deobf --show-bad-code -d $OutputDir $ApkPath
 
 $count = (Get-ChildItem -Recurse -Filter "*.java" -Path $OutputDir -ErrorAction SilentlyContinue).Count
+if ($count -eq 0) {
+    Write-Host "[ERROR] No Java files produced. Check jadx output above." -ForegroundColor Red
+    Read-Host; exit 1
+}
 Write-Host "      $count Java files decompiled." -ForegroundColor Green
 
-# 4. Analyse
+# ── 4. Analyse ────────────────────────────────────────────────────────────────
 Write-Host "`n[4/4] Analysing for BLE protocol..." -ForegroundColor Yellow
+
 $analysePy = @(
     "sniffer\analyse_jadx.py",
     "D:\Claude\HH-BT-Controller\sniffer\analyse_jadx.py"
@@ -86,12 +132,12 @@ $analysePy = @(
 if ($analysePy) {
     python $analysePy --src $OutputDir
 } else {
-    Write-Host "analyse_jadx.py not found - run it manually:"
-    Write-Host "  python sniffer\analyse_jadx.py --src $OutputDir"
+    Write-Host "  analyse_jadx.py not found, run manually:"
+    Write-Host "  python sniffer\analyse_jadx.py --src `"$OutputDir`""
 }
 
 Write-Host "`n============================================" -ForegroundColor Green
-Write-Host "  Source at: $OutputDir" -ForegroundColor Green
-Write-Host "  Browse:    code $OutputDir" -ForegroundColor Green
+Write-Host "  Done!  Source at: $OutputDir" -ForegroundColor Green
+Write-Host "  Open in VS Code: code `"$OutputDir`"" -ForegroundColor Green
 Write-Host "============================================" -ForegroundColor Green
 Read-Host "`nPress Enter to exit"