On the QBlissA9r2 (quad core) I get Overruns while on the QBlissA9 I have no problems using the same software.
So I enabled DMA as in your post about UART performance.
Is there an indication in the log to check if it is enabled? The overruns persists even with DMA registry setting and I know on the r2 there is a different UART numbering (so I tried both UART settings in registry)
At startup the device reads several 4k messages from serial port at 460k baud