The only remaining option appears to be to set the rate from `/port`. Attempts to change the rate from the line itself yield:
I've also tried to coerce it to happen via `/system scheduler` firing an on-boot script to set the rate using `/port`, but on-boot still isn't early enough to catch it before the line is in use.[admin@gns3-test] > port set [ find where name=serial0 ] baud-rate=1000000
failure: Cannot change port while in use!
Is there a way to force RouterOS to relinquish the serial line (perhaps from a telnet/SSH session) or otherwise get around the catch-22? Any advice appreciated.