Orange pi zero uart max baud rate

[Selda_bagcan]

Orange pi is only sending data with tx pin next to the ethernet port. Target is an arduino leonardo clone 5v 16mhz clocked. Maximum baud rate i could run is 115200 8bit data,no parity ,1 stop bit. Shouldnt  be i able to run at higher baud rates like 1m? Libraries i am using

https://github.com/wjwwood/serial

http://www.fourwalledcubicle.com/files/LUFA/Doc/120219/html/group___group___serial___a_v_r8.html