Generating BUP for Xavier NX

I am trying to enable A/B bootloader slot redundancy for our Xavier NX devices in the field. To update the unused slot, I am trying to create the BUP.

The TNSPEC differs between the Xavier NXs we are using. Where does this value come from?

Some examples from /etc/nv_boot_control.conf across our devices are shown below:

TNSPEC 3668----1-2-quark-mmcblk0p1
TNSPEC 3668-301-0003-B.0-1-2-cti-xavier-nx-ngx004-00-mmcblk0p1
TNSPEC 3668-300-0001-B.0-1-2-cti-xavier-nx-ngx004-00-mmcblk0p1

How can I create the BUP for each of these devices, or preferably a multi-spec one that will cover all?

I was able to generate single-spec BUPs for devices I have access to when they are connected in recovery mode, but I no longer have direct access to some of the devices with a different TNSPEC.

hello mp_ER,

you may running script file, build_l4t_bup.sh to generate BUP.
please see-also developer guide, Bootloader Update Payload Generator.
there’re two sections for generating a single-spec BUP, or a multi-spec BUP.
please refer to sample commands for reference, thanks