I own an LG-K430T, and I use it to share internet with my Desktop PC through USB tethering. Or I did it for a year straight until today, when my PC isn't recognizing my phone anymore, neither on Windows 7 nor Ubuntu 18.04.2. It doesn't even allow to share files, since there isn't a pop-up(neither in the phone nor the PC), but the phone does charge. I thought it could be my USB cable that worn off, but using this same USB cable with my sister's Huawei, it does allow to share files/internet. Furthermore, I tried with 3 different USB cables and different ports, and my phone still isn't recognized. Then, I tried it on Ubuntu, and to my surprise, it's still not recognized. So, I think it's safe to say the cable isn't the issue, nor the operative system( Also, I restarted both the phone and the PC) Then , In ubuntu, I tried to enable USB debugging followed by lsusb and nothing yet. My phone was last updated in april 2019 and its android version is 6.0, so I don't have a clue about what's causing the issue, although I'd blame the phone..
On windows,I have tried to update drivers of the 'Unknown device' on Device administration, but it says they are already up-to date
EDIT: Answers to comments: lsusb output:
Bus 003 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 007 Device 002: ID 0a12:0001 Cambridge Silicon Radio, Ltd Bluetooth Dongle (HCI mode) Bus 007 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub Bus 006 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub Bus 002 Device 003: ID 1004:6344 LG Electronics, Inc. G2 Android Phone [tethering mode] Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 005 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub Bus 001 Device 002: ID 04f9:0413 Brother Industries, Ltd Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 004 Device 002: ID 04f3:0235 Elan Microelectronics Corp. Bus 004 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub Bus 009 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub Bus 008 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
(THE LG PHONE THAT IS TETHERING IS ANOTHER ONE, DIFFERENT FROM THE ONE WITH THE PROBLEM). So, in short, lsusb doesn't recognize it. The MTP option looks already enabled
The other day a guy enabled USB debugging on my phone and got his computer to read its files!(He had a version of Windows). When I got home it worked too in my Windows! Then it downloaded some drivers and asked to reboot, which I did. After the reboot, I tried tethering and didn't work(The option to turn on was there, but when turned on, nothing happened). I thought it was because of the USB debugging and disabled developer options completely. Unfortunately, my PC stopped recognizing my phone. I said, "well, at least I can now share files..." but, surprisingly,when I turned USB-debugging back on nothing happened. Now, there is a difference which I observed between his way of activating USB-debug vs my way. It is that in his way the USB-debugging is shown active both on Settings AND in the Notification Panel(in a permanent way, i.e. it doesn't go if I press "clear all" notifications), while when I activate it,no message is shown in the notification Panel. He must have done it differently to give it more priority or something...