55.4.4.2 QSPI I/Os

QSPI_IO2 and QSPI_IO3 are dual functions and used as HOLD and WP in Dual and Serial I/O mode. As Quad mode is not the default mode, they need to be pulled up until Quad mode is enabled in the Configuration register. Pull-up resistors are not required for QSPI_IO0 and QSPI_IO1.