SMX3000HV firmware update issues

[ElCoyote777]

Hi All,

I just got a used APC SMX3000HV (no network card). It came with the 7.4 firmware and I am trying to update it to the latest firmware (15.0, it seems) using the firmware update wizard (v4.3.8).

I'm running the firmware update wizard using an USB cable from a Windows 10 Lenovo Laptop.

When I launch the firmware update wizard, it finds the UPS and properly determines that the firmware needs to be upgraded from 7.4.

Then, I follow the various prompts, select the firmware file and the UPS starts displaying 'Firmware update in progress'. Then, after just a few seconds, the UPS powers down hard (See video below) and the Upgrade Wizard on the Windows machine is stuck at:
"sending device firmware file 1 of 1 : 6%"

I waited over 10 minutes but nothing else happened. After that delay, I pressed briefly the large power button on the UPS and it came back, still on firmware 7.4.

Does anyone have any tips? How do I flash the firmware update? Must I use a serial cable? (any links to amazon cables would be helpful if that is so).

After 2 hours (yes, hours), the progress bar had moved from 6% to 10%. Should I try a serial connection instead for the firmware update?

Please help,

Thank you,

Vincent