OSPI/QSPI is a serial peripheral interface like SPI the major difference being the support for Octal/Quad read, uses 8/4 data lines for read compared to 2 lines used by the traditional SPI. This section documents how to write files to the QSPI device and use it to load and then boot the Linux Kernel using a root filesystem also found on QSPI. At this time, no special builds of U-Boot are required to perform these operations on the supported hardware. For simplicity we assume the files are being loaded from an SD card. Using the network interface (if applicable) is documented in U-boot SPI section.


Not all OSPI flashes can be supported. Users are recommended to check whether or not the OSPI flash part chosen for custom board designs meets all the criteria listed at https://e2e.ti.com/support/processors/f/791/t/946418


The sf command is used to access SPI NOR flash, supporting read/write/erase and a few other functions. For more information on sf command in U-boot please refer to the u-boot documentation: here. And for accessing SPI NAND flash, the mtd command is used, supporting read/write/erase and bad block management.

Using QSPI on AM43xx platforms is done as eXecute In Place and U-Boot is directly booted.

Writing to QSPI from U-Boot


  • From the U-Boot build the u-boot.bin file is the one to be written.

  • We load all files from an SD card in this example but they can just as easily be loaded via network (documented above) or other interface that exists.

U-Boot # mmc rescan
U-Boot # fatload mmc 0 ${loadaddr} u-boot.bin
U-Boot # sf probe 0
U-Boot # sf erase 0x0 0x100000
U-Boot # sf write ${loadaddr} 0x0 ${filesize}

Booting from QSPI

The default environment does not contain a QSPI boot command. The following example uses the partition table found in the kernel.

U-Boot # sf probe 0
U-Boot # sf read ${loadaddr} 0x1a0000 0x800000
U-Boot # sf read ${fdtaddr} 0x100000 0x80000
U-Boot # setenv bootargs console=${console} spi-ti-qspi.enable_qspi=1 root=/dev/mtdblock6 rootfstype=jffs2
U-Boot # bootz ${loadaddr} - ${fdtaddr}