I had to remake MB Serial Receive.vi from scratch, but it seems to be working... we were getting timeouts once in a while, but we were testing this through a remote desktop shared port, so there might be a tad more delays 😛
Don't mind the queues that are wired in there, they were just for debugging purposes. The inputs/outputs are named weird cause I created a snippet from the inside while loop. That boolean thing at top-left is actually a 'false' constant.
Comments / improvements / suggestions / questions are welcome...