How do I access the EPCQ configuration device on the Cyclone V GT FPGA Development Kit?.

Hello,

From my understanding, your EPCQ has programmed but corrupted. Is it possible for you to access the EPCQ via Quartus Programmer(using JTAG interface)?

You can override the EPCQ content using Quartus Programmer.

link: https://www.intel.com/content/www/us/en/docs/programmable/683375/current/programming-epcq-using-the-active-serial.html

regards,

Farabi