diff --git a/src/logic/scripting/lua/libs/libbyteutil.cpp b/src/logic/scripting/lua/libs/libbyteutil.cpp
index 54485fc1..429f0feb 100644
--- a/src/logic/scripting/lua/libs/libbyteutil.cpp
+++ b/src/logic/scripting/lua/libs/libbyteutil.cpp
@@ -137,7 +137,7 @@ static int l_unpack(lua::State* L) {
     for (size_t i = 0; format[i]; i++) {
         switch (format[i]) {
             case 'b':
-                lua::pushinteger(L, reader.get());
+                lua::pushinteger(L, static_cast<int8_t>(reader.get()));
                 break;
             case 'B':
                 lua::pushinteger(L, reader.get() & 0xFF);