diff --git a/mirai-core/src/main/java/net/mamoe/mirai/network/protocol/tim/TIMBotNetworkHandler.kt b/mirai-core/src/main/java/net/mamoe/mirai/network/protocol/tim/TIMBotNetworkHandler.kt
index e02790760..1fb4c8db8 100644
--- a/mirai-core/src/main/java/net/mamoe/mirai/network/protocol/tim/TIMBotNetworkHandler.kt
+++ b/mirai-core/src/main/java/net/mamoe/mirai/network/protocol/tim/TIMBotNetworkHandler.kt
@@ -333,7 +333,9 @@ internal class TIMBotNetworkHandler(private val bot: Bot) : BotNetworkHandler {
                         }
                         bot.notice("需要验证码登录, 验证码为 4 字母")
                         try {
-                            File(System.getProperty("user.dir") + "/temp/Captcha.png").writeBytes(this.captchaCache!!)
+                            File(System.getProperty("user.dir") + "/temp/Captcha.png")
+                                    .also { withContext(Dispatchers.IO) { it.createNewFile() } }
+                                    .writeBytes(this.captchaCache!!)
                             bot.notice("若看不清字符图片, 请查看 Mirai 目录下 /temp/Captcha.png")
                         } catch (e: Exception) {
                             bot.notice("无法写出验证码文件, 请尝试查看以上字符图片")
diff --git a/mirai-core/src/main/java/net/mamoe/mirai/network/protocol/tim/TIMProtocol.kt b/mirai-core/src/main/java/net/mamoe/mirai/network/protocol/tim/TIMProtocol.kt
index 757bcab4c..467fa7f42 100644
--- a/mirai-core/src/main/java/net/mamoe/mirai/network/protocol/tim/TIMProtocol.kt
+++ b/mirai-core/src/main/java/net/mamoe/mirai/network/protocol/tim/TIMProtocol.kt
@@ -70,7 +70,6 @@ object TIMProtocol {
      * 没有任何地方写入了这个 key
      */
     const val shareKey = "1A E9 7F 7D C9 73 75 98 AC 02 E0 80 5F A9 C6 AF"//16
-    const val fix0836 = "06 A9 12 97 B7 F8 76 25 AF AF D3 EA B4 C8 BC E7 "
 
     const val key00BA = "C1 9C B8 C8 7B 8C 81 BA 9E 9E 7A 89 E1 7A EC 94"
     const val key00BAFix = "69 20 D1 14 74 F5 B3 93 E4 D5 02 B3 71 1A CD 2A"
diff --git a/mirai-core/src/main/java/net/mamoe/mirai/network/protocol/tim/packet/login/ServerLoginResponsePasswordVerifiedPacket.kt b/mirai-core/src/main/java/net/mamoe/mirai/network/protocol/tim/packet/login/ServerLoginResponsePasswordVerifiedPacket.kt
index 5bb71bce2..8af0fb0f2 100644
--- a/mirai-core/src/main/java/net/mamoe/mirai/network/protocol/tim/packet/login/ServerLoginResponsePasswordVerifiedPacket.kt
+++ b/mirai-core/src/main/java/net/mamoe/mirai/network/protocol/tim/packet/login/ServerLoginResponsePasswordVerifiedPacket.kt
@@ -24,7 +24,6 @@ class ServerLoginResponseSuccessPacket(input: DataInputStream) : ServerPacket(in
 
 
     @Tested
-
     override fun decode() {
         this.input.skip(7)//8
         this.encryptionKey = this.input.readNBytes(16)//24
diff --git a/mirai-core/src/main/java/net/mamoe/mirai/network/protocol/tim/packet/login/Session.kt b/mirai-core/src/main/java/net/mamoe/mirai/network/protocol/tim/packet/login/Session.kt
index 21b1ed0b7..378c61f28 100644
--- a/mirai-core/src/main/java/net/mamoe/mirai/network/protocol/tim/packet/login/Session.kt
+++ b/mirai-core/src/main/java/net/mamoe/mirai/network/protocol/tim/packet/login/Session.kt
@@ -31,7 +31,7 @@ class ClientSessionRequestPacket(
             writeIP(serverIp)
             writeHex("1F 40 00 00 00 00 00 15 00 30 00 01")//fix1
             writeHex("01 92 A5 D2 59 00 10 54 2D CF 9B 60 BF BB EC 0D D4 81 CE 36 87 DE 35 02 AE 6D ED DC 00 10 ")
-            writeHex(TIMProtocol.fix0836)
+            writeHex("06 A9 12 97 B7 F8 76 25 AF AF D3 EA B4 C8 BC E7")//fix0836
             writeHex("00 36 00 12 00 02 00 01 00 00 00 05 00 00 00 00 00 00 00 00 00 00")
             writeHex(TIMProtocol.constantData1)
             writeHex(TIMProtocol.constantData2)
@@ -57,7 +57,7 @@ class ClientSessionRequestPacket(
             writeHex("68")
 
             writeHex("00 00 00 00 00 2D 00 06 00 01")
-            writeIP(InetAddress.getLocalHost().hostAddress)
+            writeIP(InetAddress.getLocalHost().hostAddress)//todo  random to avoid being banned?
         }
     }
 }