I have a supplier using the DK-DEV-5CSXC6N. Using the on-board USB-Blaster circuitry they can successfully run debug sessions on both the HPS and the FPGA. However when using an external USB-Blaster not so much.

Hi GMcSw1,

Based on your description, it seems like the USB-Blaster II is having problem as the debugging tools and USB-Blaster connection was working using on-board usb blaster. Can you try with another USB-Blaster II?

Also, can you try TCK frequency at 6MHz. 1MHz is too low and it might not working sometimes. Also, i have attached the method to configure the TCK frequency at link below, just in case you need it.

https://www.intel.com/content/www/us/en/programmable/support/support-resources/knowledge-base/solutions/rd06242013_922.html

Thank You.

Regards,

YL