diff --git a/include/ipmid/message/pack.hpp b/include/ipmid/message/pack.hpp
index 18863c4..deb0a5a 100644
--- a/include/ipmid/message/pack.hpp
+++ b/include/ipmid/message/pack.hpp
@@ -239,6 +239,10 @@
 {
     static int op(Payload& p, const std::vector<uint8_t>& t)
     {
+        if (p.bitCount != 0)
+        {
+            return 1;
+        }
         p.raw.reserve(p.raw.size() + t.size());
         p.raw.insert(p.raw.end(), t.begin(), t.end());
         return 0;