No output from HPS UART during boot

I have a custom board with a Cyclone V SoC. The chip powers up ok and I can see the FPGA and the HPS on the JTAG chain when I use my USB blaster. So far so good!

I would now like to get the HPS to boot Linux, and then configure the FPGA via Linux. All the information should come from the SD-Card.

I have an FTDI UART-to-USB chip on the HPS UART 0, so I can see the text output by the Preloader and UBOOT.

I am using a Samsung 32GB microSDHC card, configured with the relevant partitions, pre-loader, and U-boot, all generated based on my Qsys project and Quartus Prime.

When the USB cable is plugged in, the PC recognises the FTDI UART chip (as COM4), and I set the baud rate to 115200 baud, 8-bit data, no parrity, 1 stop bit, no flow control.

The problem is that when I turn on the SoC board, I see nothing coming across the UART to my PC (as viewed using Teraterm)

I appreciate that there could be all kinds of reasons why this isn't working, but I would welcome suggestions about what to check and I will try as many of those suggestions as I can.

As an initial sanity-check, can someone please confirm for me what are the correct MSEL, BOOTSEL, and CSEL settings for booting the HPS from a 3.3V SDCARD, then programming the FPGA from Linux.

Here is what I currently have selected:

http://www.alteraforum.com/forum/attachment.php?attachmentid=11900&stc=1