> I set the baud rate in the kernel options to this value (device drivers -> character devices
> -> serial drivers). Then compile and burn to flash but for some reason the baud rate remains at 19200.
Either the code that uses that configuration isn't running or something else is setting the serial port baud rate.
I don't know anything about that embedded linux specifically, just Linux in general. I assume there's a file system and processes and startup and so-on in there somewhere. I think the "init" process usually starts up the serial ports, and uses information in /etc to initialise them.
Search every file in and under "/etc" on the embedded device for "19200" or "tty" and see what you can find. If the distribution has a "skeleton" for the files that end up in /etc it might be easier to search that instead.
Otherwise arrange for system startup to run "stty" and set the ports up how you want them with that.
Tom