Cyclone V Configuration Devices

Have you looked at Cypress App Note AN200498. It says you have to tell it to ignore the Device ID of the FLASH.

We're hoping to use the Cypress chip you mention, so I hope it works. The App Note is very vague on some issues and says to contact Altera for some things like a quartus.ini file. That seemed odd. But we contacted Altera and they have no interest in helping use a competitor FLASH.

I second your comments on the Altera FLASH. Even ignoring the ridiculous price, the size ruled it out in our case. And apparently they are replacing them all with footprint compatible new chips.