Boot Modes - Boot Modes - 2026.1 English - UG1137

Zynq UltraScale+ MPSoC Software Developer Guide (UG1137)
Document ID
UG1137
Release Date
2026-07-22
Version
2026.1 English

You can use any of the following as the boot mode for booting from external devices:

  • Quad SPI flash memory (QSPI24, QSPI32)
  • eMMC18
  • NAND
  • Secure Digital Interface Memory (SD0, SD1)
  • JTAG
  • USB

The bootROM does not directly support booting from SATA, Ethernet, or PCI Express (PCIe). The boot security does not rely on, and is largely orthogonal to TrustZone (TZ). The bootROM (running on the Platform Management Unit) performs the security resources management (for example, key management) and establishes root-of-trust. It authenticates FSBL, locks boot security resources, and transfers chain-of-trust control to FSBL (either on APU or RPU).

To understand more about the boot process in the different boot modes, see the ‘Boot and Configuration’ chapter of the Zynq UltraScale+ Device Technical Reference Manual (UG1085).

QSPI24 and QSPI32

The QSPI boot mode supports the following:

  • x1, x2, and x4 read modes for single Quad SPI flash memory (QSPI24) and x8 for dual QSPI
  • Image search for MultiBoot
  • I/O mode is not supported in FSBL
Note: Single Quad-SPI memory (x1, x2, and x4) is the only boot mode that supports execute-in-place (XIP).

For additional information, see QSPI24 and QSPI32 Boot Modes.

eMMC18

The eMMC18 boot mode supports:

  • FAT 16 and FAT 32 file systems for reading the boot images.
  • Image search for MultiBoot. The maximum number of searchable files as part of an image search for MultiBoot is 8,191.

For additional information, see eMMC18 Boot Mode.

NAND

The NAND boot supports the following:

  • 8-bit widths for reading the boot images
  • Image search for MultiBoot

For additional information, see NAND Boot Mode.

SD

The SD boot supported version is 3.0. This version supports:

  • FAT 16/32 file systems for reading the boot images.
  • Image search for MultiBoot. The maximum number of searchable files as part of an image search for MultiBoot is 8,191.

For additional information, see SD Boot Mode.

JTAG

You can download any software images needed for the PS and hardware images needed for the PL using JTAG.

Important: In JTAG mode, you can boot the Zynq UltraScale+ MPSoC in non-secure mode only.

For additional information, see JTAG Boot Mode.

Zynq UltraScale+ devices do not support JTAG accesses while the CPU cores are powered down randomly by the software running on the device.

In the case of PetaLinux and Yocto embedded development framework (EDF) flows, these kernel configuration options are known to be incompatible with the JTAG debugger:

  • CONFIG_PERF_EVENTS
  • CONFIG_FREEZER
  • CONFIG_SUSPEND
  • CONFIG_PM
  • CONFIG_CPU_IDLE

USB

USB boot mode supports USB 3.0. It does not support MultiBoot, image fallback, or XIP. It supports both secure and non-secure boot mode. It is not supported for systems without DDR. USB boot mode is disabled by default. For additional information, see USB Boot Mode.