Width Detection is required for the Quad-SPI boot mode. Ensure that the BootROM
Header includes the value of 0xAA995566 so the BootROM
can determine the maximum hardware I/O data connection width of the flash device(s).
This value helps the BootROM to determine the data width of a single Quad-SPI device
(x1, x2, or x4) and to detect a second device in 8-bit parallel I/O configuration. If
this value is not present for the Quad-SPI boot mode then the BootROM lockdowns the
system and generates an error code. The error code number depends on other conditions.
The error codes are listed in Table 1. Details of the detection
operation are explained in Quad-SPI Boot.