Error (209053): Unexpected error in JTAG server -- error code 126

Description

Due to a bug in Quartus® Prime software versions 16.1, 17.0 and 17.1, the programmer may show this error when programming a volatile key into an Arria® V, Cyclone® V or Stratix® V device using a USB-Blaster download cable. This error does not occur when using a USB-Blaster II download cable to program the volatile key. 

Resolution

This problem is fixed beginning with the Intel Quartus Prime software version 18.0.