Tegraflash enhancements

As of 27 May 2020, the image_types_tegraflash.bbclass and the helper scripts have been enhanced in the branches that support L4T R32.3.1 and later (zeus-l4t-r32.3.1, dunfell, dunfell-l4t-r32.4.2, and master). This page describes the new features.

Compressed-tar instead of zip for packaging

The venerable zip archive format has worked well enough over the years, but the zip tools are quite old and don't have support for modern features like parallelism and sparse files. Switching to using a compressed tarball for tegraflash packages substantially speeds up build times and preserves sparse-file attributes for EXT4 filesystem images, resulting in much smaller (actual size vs. apparent size) packages.

In the zeus-l4t-r32.3.1 and dunfell branches, the default packaging remains zip. In dunfell-l4t-r32.4.2 and master, the default packaging has been changed to tar. You can set the variable TEGRAFLASH_PACKAGE_FORMAT in your build configuration to set the package format you want to use. Note however, that zip format is deprecated and support for it will likely be removed in a future release.

Use of bmaptool for SDcard creation

If you have the bmaptool package installed on your development host, the make-sdcard script will use it in place of dd to copy the EXT4 filesystem into the APP partition of an SDcard, which (when combined with the tar packaging mentioned above) results in much faster SDcard writing.

To take advantage of this, make sure bmaptool is available on your PATH and specify the device name of your SDcard writer when running dosdcard.sh. For example:

$ ./dosdcard.sh /dev/sda

The device name will be passed through to the underlying make-sdcard script. (If you run into permissions problems, you may need to use sudo.)

BUP payload generation

If you need to create BUP payloads outside of your bitbake builds, the tegraflash package now includes all of the files needed to do so, including a script to create the payload (similar to the l4t_generate_soc_bup.sh script in L4T):

$ ./generate_bup_payload.sh

You can pass the -u and/or -v options to this script to specify the public and/or private keys for signing the payload contents if your devices are fused for secure boot, and they will be passed through to each invocation of the flash helper script.