diff --git a/src/reticulum/LXMFMessage.cpp b/src/reticulum/LXMFMessage.cpp
index cd04c92..7863ed3 100644
--- a/src/reticulum/LXMFMessage.cpp
+++ b/src/reticulum/LXMFMessage.cpp
@@ -155,8 +155,14 @@ bool LXMFMessage::unpackFull(const uint8_t* data, size_t len, LXMFMessage& msg)
     if (!mpReadString(content, contentLen, pos, msg.content)) return false;
     if (arrLen >= 4 && pos < contentLen) { mpSkipValue(content, contentLen, pos); }
 
-    RNS::Bytes fullPayload(data, len);
-    msg.messageId = RNS::Identity::full_hash(fullPayload);
+    // messageId = SHA256(dest + src + packed_content), matching Python/Rust
+    // (skip signature at bytes 32..96)
+    std::vector<uint8_t> hashInput;
+    hashInput.reserve(32 + (len - 96));
+    hashInput.insert(hashInput.end(), data, data + 32);       // dest_hash + src_hash
+    hashInput.insert(hashInput.end(), data + 96, data + len);  // packed_content
+    RNS::Bytes hashable(hashInput.data(), hashInput.size());
+    msg.messageId = RNS::Identity::full_hash(hashable);
     msg.incoming = true;
     msg.status = LXMFStatus::DELIVERED;
     return true;