diff --git a/app/src/main/java/com/example/medilightv2android/ble/BleManager.kt b/app/src/main/java/com/example/medilightv2android/ble/BleManager.kt
index fa14a96..20cab69 100644
--- a/app/src/main/java/com/example/medilightv2android/ble/BleManager.kt
+++ b/app/src/main/java/com/example/medilightv2android/ble/BleManager.kt
@@ -354,7 +354,7 @@ class BleManager private constructor(private val context: Context) {
     }
 
     fun sendLedMode(state: Int) {
-        sendRaw(CRC16.buildCommandASCII("mls", " $state"))
+        sendRaw(CRC16.buildCommandBE("mls", intArrayOf(state)))
     }
 
     fun sendImuQuery() {
diff --git a/app/src/main/java/com/example/medilightv2android/ble/CRC16.kt b/app/src/main/java/com/example/medilightv2android/ble/CRC16.kt
index 28cdbe9..689b2ba 100644
--- a/app/src/main/java/com/example/medilightv2android/ble/CRC16.kt
+++ b/app/src/main/java/com/example/medilightv2android/ble/CRC16.kt
@@ -54,6 +54,17 @@ object CRC16 {
         return appendCRC("$cmd?$asciiParams".toByteArray(Charsets.UTF_8))
     }
 
+    /** 파라미터를 16비트 Big Endian으로 추가 (펌웨어 테스터와 동일 포맷) */
+    fun buildCommandBE(cmd: String, params: IntArray = intArrayOf()): ByteArray {
+        val cmdBytes = "$cmd?".toByteArray(Charsets.UTF_8)
+        val paramBytes = ByteArray(params.size * 2)
+        for (i in params.indices) {
+            paramBytes[i * 2] = ((params[i] shr 8) and 0xFF).toByte()  // High byte first
+            paramBytes[i * 2 + 1] = (params[i] and 0xFF).toByte()      // Low byte
+        }
+        return appendCRC(cmdBytes + paramBytes)
+    }
+
     fun buildSimpleCommand(cmd: String): ByteArray {
         return appendCRC(cmd.toByteArray(Charsets.UTF_8))
     }