Starling D0005 / VOXL 2 M0054-2 still stuck in Qualcomm 900e after QDL reflash

[alraj]

I am trying to recover a Starling D0005 with a VOXL 2 M0054-2.

The board previously worked normally over ADB, but it now always shows up as:

05c6:900e Qualcomm QUSB_BULK
VOXL USB serial: c1abd993
Qualcomm serial: D3323EEF

I have SW2 set to OFF and have performed several full power cycles, but the board never appears in ADB or Fastboot.

Before the failure, voxl-version reported:

hw_platform: M0054
mach.var: 1.2.0

Based on that, I used the documented QDL recovery image for the Starling D0005 / M0054-2:

2024-02-09-1.7.4-M0054-2

The QDL process completed successfully. Sahara and Firehose communication worked, and the tool programmed the full image, which was approximately 3.2 GiB. The board then reset and re-enumerated.

However, after removing power, setting SW2 back to OFF, and booting normally, it returned to the same 05c6:900e state.

I was also able to capture a read-only Qualcomm Sahara crash dump. It is approximately 8.1 GiB and contains four 2 GiB DDR regions, along with OCIMEM, PIMEM, reset data, and PMIC metadata. I have not uploaded it publicly because it may have sensitive memory contents.

Has anyone encountered this before?

Does a persistent 900e state after a successful flash with the correct M0054-2 image usually indicate a hardware failure?
Is there another recovery procedure I should try before contacting ModalAI for repair or an RMA?