diff --git a/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/utils/io/output.kt b/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/utils/io/output.kt
index 803e579a6..38077fe9e 100644
--- a/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/utils/io/output.kt
+++ b/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/utils/io/output.kt
@@ -41,7 +41,7 @@ inline fun BytePacketBuilder.writeShortLVByteArray(byteArray: ByteArray): Int {
 inline fun BytePacketBuilder.writeIntLVPacket(tag: UByte? = null, lengthOffset: ((Long) -> Long) = {it}, builder: BytePacketBuilder.() -> Unit): Int =
     BytePacketBuilder().apply(builder).build().use {
         if (tag != null) writeUByte(tag)
-        val length = lengthOffset.invoke(it.remaining).coerceAtMostOrFail(0xFFFFL)
+        val length = lengthOffset.invoke(it.remaining).coerceAtMostOrFail(0xFFFFFFFFL)
         writeInt(length.toInt())
         writePacket(it)
         return length.toInt()
@@ -50,7 +50,7 @@ inline fun BytePacketBuilder.writeIntLVPacket(tag: UByte? = null, lengthOffset:
 inline fun BytePacketBuilder.writeShortLVPacket(tag: UByte? = null, lengthOffset: ((Long) -> Long) = {it}, builder: BytePacketBuilder.() -> Unit): Int =
     BytePacketBuilder().apply(builder).build().use {
         if (tag != null) writeUByte(tag)
-        val length = lengthOffset.invoke(it.remaining).coerceAtMostOrFail(0xFFFFL)
+        val length = lengthOffset.invoke(it.remaining).coerceAtMostOrFail(0xFFFFFFFFL)
         writeUShort(length.toUShort())
         writePacket(it)
         return length.toInt()