I'm looking to use 460800. 115200 works without issue.

I'm looking at a similar problem. Seems that UARTs only support a few baud rates, due to the the default clock divider settings APB2: https://github.com/friendlyarm/h3_lichee/blob/master/linux-3.4/drivers/tty/serial/sunxi-uart.c#L357 I posted in the bootloader section with the same question. Hoping ...

Hello, I'm having an issue with the NanoPi Neo Air UART baud rates. It seems that the default clock divider only supports a few baud rates: https://github.com/friendlyarm/h3_lichee/blob/master/linux-3.4/drivers/tty/serial/sunxi-uart.c#L357 Any suggestions to be able to modify the APB2 clock settings...