Thank You all!
I was confused by the fact that someone said that he had this feature on Oneplus 3.
So...
I hope we will have this in nearest future.
Have a nice day!

Hello!
I've not been to this forum for a long time.
I already had some experience with ubuntu on my Oneplus One and also on Oneplus 3.
Then there were some video playback issues (though not only that).
I am talking about the MP4 format.
On Oneplus 3 video was not played at all.
And only short video (approximately 5-10 minutes) was played on Oneplus One.
So questions to Ubuntu Touch users of all smartphone models:
Does your smartphone model play 50+ min or 500+ MB video?
Please give me an answer in the format like:
My model is ... - the problem with the video is the same as yours
or
My model is ... - I have no problems with the video.
Thank You All in advance.
Kyrylo.

@slowcyclist Thank You very much!

I've just copied and pasted some of lines from your topic and USB-tethering WORKS NOW!!!
(I don't know why )
Here are that commands:
$ sudo android-gadget-service enable rndis
$ sudo bash /android/system/halium/usr/share/usbinit/setupusb reset
$ sudo bash /android/system/halium/usr/share/usbinit/setupusb rndis
$ sudo ifconfig rndis0 up
$ sudo tethering enable

Please, test it sombody else with Oneplus3.

@Lakotaubp
Yep!
I can mistaken, maybe order should be different.
I've just messed up with those commands and suddenly it worked.

@Xray2000 Thank You very much. Could you tell me how i can know for which version of stock image this recovery is, or whether it does metter? And maybe someone has exprience in returning to stock condition and can give me some advices and valid links.
I found a lot of outdated tutorials and broken links so l prefer to ask You help to be sure I'll be able to do everything right.
I will appreciate a lot.

@Xray2000 By the way, I've downloaded recovery from other source than your link earlier. That was recovery for Oxygen OS 4. But sha256sums of both images are the same.
So I don't know if I can trust this recovery and where I can get recovery for OxygenOS 9.0.6 available now.
Any suggestions?

@tigerpro Thank You VERY MUCH!
This can help me choose the smartphone model I need.

@moem Thanks for your reply.
But what's the use of video recording with my OPO's camera if I can't even check if it's a good take?
P.S.: anyway if you can help me, I'll be grateful.

Hello!
I've not been to this forum for a long time.
I already had some experience with ubuntu on my Oneplus One and also on Oneplus 3.
Then there were some video playback issues (though not only that).
I am talking about the MP4 format.
On Oneplus 3 video was not played at all.
And only short video (approximately 5-10 minutes) was played on Oneplus One.
So questions to Ubuntu Touch users of all smartphone models:
Does your smartphone model play 50+ min or 500+ MB video?
Please give me an answer in the format like:
My model is ... - the problem with the video is the same as yours
or
My model is ... - I have no problems with the video.
Thank You All in advance.
Kyrylo.

@commisde Hey!
If I'm not mistaken there is no problem with USB-tethering on Nexus 4.
You should just type those two commands in terminal:

$ android-gadget-service enable rndis
$ sudo tethering enable

@Lakotaubp
Yep!
I can mistaken, maybe order should be different.
I've just messed up with those commands and suddenly it worked.

@slowcyclist Thank You very much!

I've just copied and pasted some of lines from your topic and USB-tethering WORKS NOW!!!
(I don't know why )
Here are that commands:
$ sudo android-gadget-service enable rndis
$ sudo bash /android/system/halium/usr/share/usbinit/setupusb reset
$ sudo bash /android/system/halium/usr/share/usbinit/setupusb rndis
$ sudo ifconfig rndis0 up
$ sudo tethering enable

Please, test it sombody else with Oneplus3.

Thank You all!
I was confused by the fact that someone said that he had this feature on Oneplus 3.
So...
I hope we will have this in nearest future.
Have a nice day!

@gischpelino Your idea sounds good.
Thank you for clarifying the question.

@Lakotaubp No results with UT Tweak Tool.
Is it common issue?
Has anybody USB-tethering working on OP3?

Hello!
I have a issue with usb-tethering.
When I type in terminal
$ android-gadget-service enable rndis
rndis enabled
$ sudo tethering enable
Device "rndis0" does not exist.
Error: Connection 'tetherning' does not exist.

I have had this problem for a long time. I installed the new version several times, but to no avail.
This feature worked fine on Android, but does not work on UBports.

Does anyone have any idea where to look for the cause of the fault?
Thanks in advance.