Cyclone 3 configuration: Nios2, JTAG, multiple fpga, 1 EPCS16

[Altera_Forum]

In other projects, we've always only used one EPCS4/16 device to configure one FPGA (cyclone, cyclone3). We configured with the Nios2 and EPCS controller peripheral through JTAG after loading the SOF file. 

 We'd like to do the same thing, but now with 2 separate cyclone 3c25 parts with only one ECPS16 device using Nios2 and the ECPS controller peripheral with JTAG. Is this even possible? How would the configuration/firmware files be partition? Any direction or hint would be appreciated.

[Altera_Forum]

Chaining two FPGA configurations isn't a problem. It is well explained in this document (http://www.altera.com/literature/hb/cyc3/cyc3_ciii51016.pdf), pages 9-15 and over. 

For the software it is a bit more complicated because the bootloader expects to find the .elf file just after the first SOF image in the flash. In your case you will have the second SOF file for the other FPGA at that position, so the bootloader will fail. You will need a custom bootloader in the first FPGA to load the embedded software. this an (http://www.altera.com/literature/an/an458.pdf) can help. For the second FPGA it is even more complicated because it is connected as passive serial and can't control the EPCS flash. You will also need a custom bootloader, and it will be up to the first FPGA to somewhat send the software image to the second one.