STTY arbitraty baudrate

[lesto fante]

Hello,

i'm working on some MCU and i need to set arbitrary baudrate; looking
at the code of stty seems like I can only use a baudrate from a
specific list.

I undertstand those are standard and non-standard things can make
issue, but could it possible to use a flag to say "look stty, i know
waht im doing, give me my 250.000 baud thanks."

>From what I seen ospeed and ispeed seems to bypass the check, maybe
the solution would be to set this in a manual?