[guybrushthreepwood]

My best regards. My 'problem' is already solved (I've solved it brutally removing usb-modeswitch from my Lubuntu 23.10 system because it has been immediately clear to me that something wrong was happening with switching which kept cycling forever and I don't need switching anyway given that I use the WiFi interface) but I'm opening this thread anyway in the hope to be of help to the developers and/or someone else who owns the same crap.
I'm talking about one of those cheap 4G (not even sure it's actually LTE given that the best I can get are HSDPA speeds) dongles being sold almost everywhere online. What I believe is its marketing name is 4G UFI (also its SSID along with a 'unique' identifier appended) while here:

Firmware version: 01.01.02
Software version: QR91F_V5.0_Oct 21 2019 Hardware version: HV1.0

are the further details I can get from its web interface reachable at 192.168.100.1. Under Windows it also works in modem mode after installing the needed drivers along with a dashboard while under Lubuntu, as written in the subject of the thread, it keeps switching forever, every thirty seconds or so, this rendering WiFi unusable (I use it in WiFi mode to provide with an internet connection other devices too but I often use it plugged into my laptop and this is how the 'problem' arose).
As soon as I plug it, I get a popup window showing the error:

Unable to open MTP device "002,036"

which I believe is related to the missing MTP support on my system (probably mtp-tools and maybe something else too but I don't care about that), certainly not usb-modeswitch but then the switching cycle begins and I was forced to solve it as described at the beginning.
Here is the device I get issuing an lsusb as soon as I connect it:

Bus 002 Device 036: ID 05c6:f000 Qualcomm, Inc. TA-1004 [Nokia 8]

which seems to confirm the theory I've read around that these dongles are built with parts recycled from broken (and/or discarded during production because of manufacturing defects) smartphones given that it isn't a Nokia 8 for sure!
Again, my 'problem' is solved (the reason why I've always wrapped the word "problem" with quotation marks is that I don't believe that there is anything wrong with usb-modeswitch itself but it's just a matter of lack of support for this peculiar HWID or maybe some kind of fault with the dongle given its poor quality) and I've opened this thread not to my advantage but in the hope it could be useful (though I would understand if the developers wouldn't have any interest at working at such this kind of device, probably not so widespread). I remain free to help if asked to. A nice day to everyone!

[sonabin]

From what you describe, it seems that the “4G UFI” device you are using is indeed one of those cheap dongles with “strange” hardware, most likely assembled from recycled components as you suspect. The fact that it is identified as Qualcomm/Nokia 8 (05c6:f000) is quite consistent with the hypothesis that the device originated from an old smartphone.
Suika game

[sohebre]

Based on your description, your "4G UFI" device is a cheap portable USB WiFi hotspot, commonly sold as "4G LTE USB Modem", "4G UFI", etc. Usually inside it is a 3G/4G modem that can operate in the following modes:

Modem (using via USB, requires driver and modeswitch) hole io online

WiFi router (broadcasting WiFi to other devices without driver)

[rosebl22]

Stickman Hook Do you know of any branding, vendor, or marketplace listing that consistently sells this dongle, in case developers want to acquire one for testing?

[straightforward]

Users suggest that the problem may not be with USB - World Guesser modeswitch but rather with a lack of support for the device's specific HWID or with poor quality of the dongle itself.

[emmascott11]

I just wanted to add that I’ve encountered similar behavior on a nearly identical 4G UFI dongle (same firmware version and web interface at 192.168.100.stickman hook1). In my case, the looping switching issue also vanished after removing usb-modeswitch, but I can confirm that this effectively disables any attempt to use the dongle in modem mode via USB. Like many of you, I primarily rely on WiFi mode anyway, so it’s a livable workaround.