Hi, @tooz
Based on the spec of rk3288, I think it should be able to support baud rate higher than 115200.
I need to communicate with another module with 230400.
I also tried that on Tinker Board 2S and the incoming text is correct but the sent data from Tinker Board is corrupted.
the dmesg from Tinker Board 2S is something like
invalid destination resolution act_w = 0, act_h = 0
rga: req argument is inval
ttyS0 - failed to request DMA, use interrupt mode
I have tried another dev board Rock Pi 4 which is also based on rk3399 and that works well with 230400.