This is just in general, I do not know about your particular case. Some general information…
The TX2 uses a tegra18x series, specifically the tegra186, abbreviated t186. The a02 would be a board revision, the “pxxxx” is abbreviated for the numeric designation of either the module or the carrier (so you might need to adjust specifics for your module and carrier). Depending on release, look in the driver package’s “bootloader/t186ref/” subdirectory. Various device tree files will be there, and flash would choose among those depending on what the board is (the numeric designation would have one version for module, a second version for carrier would combine to be a complete description of module on carrier). My TX2 developer kit happens to be described from “p3310-1000”. Different trees may apply to different subsets of module and carrier, whereby different smaller trees might be inserted into the final full tree.
Flash logs on my particular TX2 under R28.2 shows:
copying bpfdtbfile(/home/dan/Documents/embedded/L4T/R28.2/x2/Linux_for_Tegra/bootloader/t186ref/<b>tegra186-a02-bpmp-quill-p3310-1000-c01-00-te770d-ucm2.dtb</b>)... done.
The first dtc operation, with “-I dtb”, takes the binary file as input, and the output format is source, via the “-O dts”. File name output can be arbitrary, and in that example, “-o test_bpmp.dts”. You can view, manipulate, edit, and place this extracted file back into binary format and use it to replace the one used in the “bootloader/” subdirectory during flash.
Note that within the “Linux_for_Tegra/” subdirectory, where the driver package exists, that the log above shows the original file in “bootloader/t186ref/tegra186-a02-bpmp-quill-p3310-1000-c01-00-te770d-ucm2.dtb” (and other dtb files) can be copied from other locations for staging before flash. Subdirectories of the “bootloader/” directory are worth exploring after looking at “copy” logs from a flash.