Why does the HPS fail to reboot in Intel® Stratix® 10 and Intel Agilex® 7 SoC FPGAs?

Due to a problem in the Intel® Quartus® Prime Pro Edition Software version 21.3 and later, the HPS may fail to reboot using the 'reboot' command in Linux if both the following conditions are true:

• The device is programmed via JTAG 
• MSEL is set to ASx4 mode.

Toggling nCONFIG may not have an impact on the behavior and the device may require a power cycle. This is known to impact all Intel® Stratix® 10 SoC and Intel Agilex® 7 SoC FPGA designs. 

This problem is fixed starting with the Intel® Quartus® Prime Pro Edition Software version 21.4.