How to flash UDA partition with initrd flashing?

[Schlumpf]

I would like to use the UDA partition to store some data permanently when I use OTA updates with A/B boot.
Therefore I created an ext4 partition and set the variables DATAFILE and IMAGE_TEGRAFLASH_DATA to thar file. But while flashing, the partition is not being flashed:

...
== Step 4: Writing partitions on external storage device at 2026-05-13T11:09:03+02:00 ==
Waiting for USB storage device nvme0n1 from 8e816158...[/dev/sda]
Creating partitions
  [03] name=A_kernel start=0 size=262144 sectors
  [04] name=A_kernel-dtb start=0 size=1536 sectors
  [05] name=A_reserved_on_user start=0 size=64768 sectors
  [06] name=B_kernel start=0 size=262144 sectors
  [07] name=B_kernel-dtb start=0 size=1536 sectors
  [08] name=B_reserved_on_user start=0 size=64768 sectors
  [09] name=recovery start=0 size=163840 sectors
  [10] name=recovery-dtb start=0 size=1024 sectors
  [11] name=esp start=0 size=131072 sectors
  [12] name=recovery_alt start=0 size=163840 sectors
  [13] name=recovery-dtb_alt start=0 size=1024 sectors
  [14] name=esp_alt start=0 size=131072 sectors
  [15] name=UDA start=0 size=819200 sectors
  [16] name=reserved start=0 size=982016 sectors
  [01] name=APP start=0 size=10485760 sectors
  [02] name=APP_b start=0 size=10485760 sectors
Writing partitions
  Writing boot.img (size=46790656) to /dev/sda3 (size=134217728)...
  Writing kernel_tegra234-myboard+p3767-0003-nv-super.dtb (size=262803) to /dev/sda4 (size=786432)...
  Writing boot.img (size=46790656) to /dev/sda6 (size=134217728)...
  Writing kernel_tegra234-myboard+p3767-0003-nv-super.dtb (size=262803) to /dev/sda7 (size=786432)...
  Writing esp.img (size=67108864) to /dev/sda11 (size=67108864)...
  Writing myimage.ext4 (size=5368709120) to /dev/sda1 (size=5368709120)...
  Writing myimage.ext4 (size=5368709120) to /dev/sda2 (size=5368709120)...
[OK: /dev/sda]
== Step 5: Waiting for final status from device at 2026-05-13T11:14:02+02:00 ==
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I use an Orin Nano with NVME on a custom board and ./initrd-flash. What am I missing?

[madisongh]

The commit 6258ce7 fixed this for Thor/R38.4.x flashing. It probably won't patch cleanly for the R36.x-based branches, but should be pretty close.

[Schlumpf]

Many thanks. The initrd-flash.sh from R36.x looks quite different, but I found the issue:

The default flash_l4t_t234_nvme_rootfs_ab.xml is missing the tag <filename> DATAFILE </filename> in the UDA partition. After adding this tag it got flashed without patching the initrd-flash.sh.