Why does Mailbox Client Intel® FPGA IP returns HW_NOT_READY for subsequent QSPI commands, despite a successful QSPI_OPEN request?

The problem may be seen in the Intel® Quartus® Prime Pro Edition Software version 23.2 when running QSPI commands after a successful QSPI_OPEN. The QSPI_OPEN returns “OK,” but subsequent QSPI commands return the error “HW_NOT_READY.”

It is affecting Intel Agilex® devices only.

This is due to an SDM firmware change in Intel® Quartus® Prime Pro Edition Software 23.2.

To workaround this problem, run the QSPI_SET_CS commands after every QSPI_OPEN.

If the workaround is not applicable, please file a request to Intel® for support.