Hi,
are you trying to write to the FPGA an image or are you trying to place a HEX file in flash device? The CII should be configured with a SOF. A FPGA does not execute software it is hardware and can only be configured through an image. What you can do is using a soft core processor as a hardware implementation and run that in the FPGA. Then this softcore processor like Nios can execute software. What application are you running and what are your plans?
If you want to write it to a flash device you could search for how to write to a flash with a JIC.
Cheers,
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