Finally. I think I nailed the bug in Blunt which caused the random restarts. Or rather, I replaced the code which I suspected to be not working. The root cause was clear, data being received with no place to store. In the original TAsyncSerTool, the data is left in the input buffer, and before, I was removing it and storing it in a temporary buffer in Blunt. Now I just check if a HCI packet is complete, and if not, I just leave it in the input buffer. Seems to work quite nicely, so everybody having trouble with Blunt causing restarts should switch to 0.7.6!