84+ boot code OS-sending exploits: 1. Using this method, you can't send data to pages 1-3. Just send everything as normal, but send page 0 last with the offsets as 00:4xxxh, not 00:0xxxh. 2. Using this method, you can send data anywhere. Send everything like normal (even page 0 with 0FFh at 0056h), then when you're done, send data to be received to FF:7FFFh (send 57h bytes, the first can be garbage, the next 55h should be 00:0000h-0055h, and the last should be 5Ah).