[Nut-upsuser] tripplite_usb driver failing with libusb_get_interrupt() returned 0 and ###NOTMATCHED-YET### bcdDevice = "000A"

[Charles Lepple]

On Sep 21, 2026, at 11:01 PM, Jeff Hood via Nut-upsuser <nut-upsuser at alioth-lists.debian.net> wrote:
> Hi everyone,
> 
> I'm running Network UPS Tools (NUT) version 2.8.1 on a Debian system (aarch64), trying to connect an older Tripp Lite UPS via the tripplite_usb driver.
> 
> While nut-scanner -U successfully identifies the hardware, it flags the device's firmware revision with a ###NOTMATCHED-YET### notice:
> 
I don't use nut-scanner, but I think it will do that for any USB device: https://github.com/networkupstools/nut/blob/v2.8.1/tools/nut-scanner/scan_usb.c#L590

> When the driver service attempts to start, it successfully claims the USB endpoint but falls into an endless retry loop during the command handshake:
> libusb_get_interrupt() returned 0 instead of 8 while sending 3a 55 aa 0d 00 00 00 00 '.U......'

I'd check several things:

1) Are there any other communication ports connected to the UPS? There is the obvious serial port, but also check for a network card - under the hood, most older Tripp-Lite UPSes seem to only have a single serial path to the controller, so you can't use more than one port at a time (and the USB port is just a USB-to-serial converter inside).

2) Does the problem go away if you reset the UPS? It probably needs a hard power-down, where you remove line power for a minute or so.

3) Does this work on a PC? I realize that setting up a PC can be a bit of a pain, but maybe a Live CD would be sufficient. I developed the tripplite_usb code on an early 2000's x86 home PC, and when Tripp-Lite came out with 3016 protocol devices, they were not reliable with higher-end server chipsets that supported USB 2.0. (That problem even manifested itself with non-NUT software like lsusb, but it was more evident in NUT since lsusb runs briefly and exits.) I'm concerned that the aarch64 USB support may be different yet.

It would be interesting to know more about the specific Tripp-Lite model in question.

-- 
Charles Lepple
clepple at gmail
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