ADUCM355 maximum UART baud rate and SINC3 filter for ADC

Dear suppor team,

I am working on a serial voltage ADC, sampling rate 200kSps, with just SINC3 OSR4 enabled and saved to FIFO.

I have two questions. 

1. I wanted to see if the SINC3 can be bypassed (ODR at 800kSps) but somehow, the FIFO or polling becomes unstable. 

Can you please guide me through?

Also, I was not able to find any documented information about SINC3 and SINC2.

Is there any reference material other than going through the codes?

2. In the UrtLib.h, the maximum baud rate is 430,800 but I was not able to get it working. 

Is there a way for a higher baude rate (>230400)? 

Otherwise, I would have to consider SPI over USB...

Thank you!