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tegra-bootloader-update

This tool replaces the L4T nv_update_engine tool for TX2/Xavier systems and the l4t_payload_updater_t210 tool for TX1/Nano systems. It applies a bootloader update payload (BUP) generated by the L4T flashing tools.

For T186/T194 platforms

On TX2/Xavier platforms, the typical use case for tegra-bootloader-update is to apply a BUP as part of an OTA full rootfs installation when implementing a full A/B update strategy.

Differences from nv_update_engine

  • No need for the /etc/nv_boot_control.conf file. The TNSPEC used to determine boot component compatibility is directly derived from the CVM EEPROM contents.
  • No nv_update_verifier service at boot time. Such a service could be implemented, if desired, but for full A/B upgrades that include the rootfs, the verify-and-overwrite feature of the L4T update verifier is undesirable.
  • The tool can be used to completely initialize all boot components, provided the BUP payload contains all of them (default BUP generation in L4T does not do this).
  • This tool compares the contents of each boot component from the current content before updating and skips unneeded writes, saving update time on Xavier NX systems that store boot components in QSPI flash.
  • This tool automatically enables A/B redundancy during an update if it has not yet been enabled.

A script is included that emulates a subset of the nv_update_engine command-line interface using tegra-bootloader-update.

For T210 platforms

The TX1/Nano platforms do not support A/B updates for the bootloaders, and you must take that factor into consideration when implementing your update strategy. They do implement redundancy for the boot partitions, but only as a fallback used should there be a failure during an update.

The tegra-bootloader-update tool can be used for applying BUPs on TX1/Nano platforms, replacing the l4t_payload_updater_t210 script included in the L4T BSP.

Differences from l4t_payload_updater_t210

  • Written in C, rather than Python.
  • Boot partition information is read from a configuration file at runtime, rather than being hard-coded into the tool.
  • Automatically handles either SPI flash or eMMC boot partitions, without depending on the MACHINE name as the Python tool does.