android: lifetime query + cali consistency check + real-device checklist

android/app/src/main/kotlin/com/mag160c/thermal/usb/IrSession.kt

@@ -110,6 +110,11 @@ class IrSession(context: Context) {
     var lastInfo1: ByteArray? = null
         private set
 
+    /** Device power-on lifetime in ms (official getDevLifeTime); -1 = unknown. */
+    @Volatile
+    var deviceLifetimeMs: Long = -1
+        private set
+
     fun identitySnapshot(): CameraIdentity = identity.copy()
 
     /** Connect + start the live stream. Must be called after USB permission. */
@@ -207,6 +212,24 @@ class IrSession(context: Context) {
         }
         DebugLog.log("session", "cali info: size=$caliSize date=$caliDate")
 
+        // 3b) GetLifeTime (official getDevLifeTime): 675 -> 0x5BB5B561 {magic, ms}.
+        // Non-blocking: the official app just logs when this fails.
+        writeCmd(conn, epOut, MagProtocol.cmd4(MagProtocol.CMD_GET_LIFETIME), "GetLifeTime")
+        readResp(conn, epResp, "GetLifeTime")?.let { r ->
+            if (r.second == MagProtocol.RSP_SEND_LIFETIME) {
+                // protocol doc: payload {magic, i32 ms}; official Java reads the
+                // bare {i32 ms} right after the response magic — accept both.
+                val ms = when {
+                    r.third.size >= 8 && MagProtocol.u32(r.third, 0) == MagProtocol.RSP_SEND_LIFETIME ->
+                        MagProtocol.u32(r.third, 4)
+                    r.third.size >= 4 -> MagProtocol.u32(r.third, 0)
+                    else -> null
+                }
+                if (ms != null) deviceLifetimeMs = ms.toLong() and 0xFFFFFFFFL
+            }
+        }
+        DebugLog.log("session", "device lifetime=${deviceLifetimeMs}ms")
+
         // 4) calibration file: cache hit or fetch from EP 0x84
         val ddt = obtainCali(conn, ep84, epOut, epResp, caliSize, caliDate, bundledDdt)
         DebugLog.log("session", "ddt bytes ${ddt.size}")
@@ -294,7 +317,14 @@ class IrSession(context: Context) {
         if (cache.isFile && cache.length() == size) {
             DebugLog.log("session", "cali cache hit: ${cache.name}")
             return try {
-                cache.readBytes()
+                val cached = cache.readBytes()
+                // consistency check only: the cache stays authoritative
+                DebugLog.log(
+                    "session",
+                    "cali cache vs bundled DDT: " +
+                        if (md5(cached).contentEquals(md5(bundled))) "identical" else "differ",
+                )
+                cached
             } catch (e: Exception) {
                 DebugLog.log("session", "cali cache read failed -> bundled: $e")
                 bundled
@@ -349,6 +379,10 @@ class IrSession(context: Context) {
         return out
     }
 
+    /** MD5 digest of a byte array (cali consistency check only). */
+    private fun md5(bytes: ByteArray): ByteArray =
+        java.security.MessageDigest.getInstance("MD5").digest(bytes)
+
     private fun notify(state: State, message: String?) {
         DebugLog.log("session", "state -> $state msg=$message")
         listener?.onStateChanged(state, message)
@@ -516,7 +550,8 @@ class IrSession(context: Context) {
                     "stream",
                     "stats: reads=$readCount frames=$frameCount rendered=$renderCount " +
                         "timeouts=$timeouts fps=%.1f ".format(Locale.US, fps) +
-                        "renderState=${pipe.frameIndex()} ref=${pipe.hasReference()}",
+                        "renderState=${pipe.frameIndex()} ref=${pipe.hasReference()}" +
+                        " lifetime=${deviceLifetimeMs}",
                 )
                 lastLog = now
             }

android/app/src/main/kotlin/com/mag160c/thermal/usb/MagProtocol.kt

@@ -31,6 +31,9 @@ object MagProtocol {
     const val RSP_SEND_CALI_FILE = 0x5BB5B55D
     const val RSP_SEND_CALI_INFO = 0x5BB5B55E
 
+    /** D2P_SendLifeTime (1538635105) — reply to GetLifeTime: {u32 magic, i32 ms}. */
+    const val RSP_SEND_LIFETIME = 0x5BB5B561
+
     /**
      * 4-byte LITTLE-ENDIAN command — byte-identical to the official app's
      * GlobalFunc.intToByteArray (a&255 first).  CRITICAL: ByteBuffer.putInt