Error after upgrading to 17.10 from 16.04

[Poleh]

Hi Folks

gnarly problem, which I am stuck with and would appreciate any help that you can provide.

Background
I manage my Mom's System76 box remotely and have done for quite a few years. Works fine, TeamViewer is my friend and it's been pretty rock solid.

Over the weekend, I decided to upgrade her to 17.10 from 16.04 - used the command line and did a full update before a release upgrade. All seemed to go well until at some point (I guess on first reboot) I couldn't get back into the system via TeamViewer - always a warning flag on my end that something has gone wrong. Apparently the "screen was black" and not responding - this after many hours after the upgrade was started.

The catch is, her machine is in Africa, and there's a very real chance there may have been a power failure at some point.

The Error
Right now, when she boots the machine, there's a brief flash of purple boot screen, and then we are left with the following message:

Scanning for Btrfs filesystems
Ubuntu: clean, 261754/7036928 files, 4040009/28124928 blocks
[ 494.721506] usb 3-6: device not accepting address 8, error -71

My challenge
Diagnosing this remotely without access is tough, so I am reduced to hosting a phone based hangouts video call with my Mom pointing the camera at the screen so I can see what's going on :) #funtimes

I have researched this error message, and came up with very little that was applicable on initial investigation. It's also important to note that I am also passably capable with Ubuntu and Linux in general - reasonably comfy on the command-line, but not deeply knowledgeable.

I am looking for suggestions on next steps to get the machine booting to a point where I can either remote SSH in, or get a GUI going with TeamViewer so I can clean up further. Any and all help is greatly appreciated.

[DuckHook]

Remote administration is a bad idea on top of a GUI. Far too many additional points of failure. Teamviewer is not even native to Linux, but a Windows port that often misbehaves. Then you went and did a full release-upgrade remotely, across continents, which is sort of like saying: since I've dodged many bullets up to now and even the occasional cannonball, I think I'll try dodging a nuclear missile this time.

Don't. Do. This.

As for unscrambling this egg:


Is your Mom's important data backed up? That's the first thing I would do if I were her.
How knowledgeable is your Mom? The least painful solution may be to simply have her reinstall, then restore data from backups.
Why are you going to Artful? Is there some Xenial limitation that she can't live with?
What odd things have been done to this machine? btrfs is not part of a default Xenial install. Please list all of your customizations (i.e. additions to/departures from a default install).
Power failures are ubiquitous in some parts of Africa. Is she on battery backup when updating/upgrading? Especially when release-upgrading?
Does your Mom have access to another computer on which she can create a LiveUSB? The idea would be to run a live session and at least be able to backup. This also allows her to chroot into the broken machine.

I'll be brutally candid:

Your chances of successfully rescuing a failed release upgrade halfway across the world are very poor. Rescuing regular upgrades or the occasional dpkg error is not too bad, but release upgrades are a completely different kettle of fish. As my sig tagline says: they are heart, lung and brain transplants. Since you suspect that a power failure occurred during the process… well… the outlook is very bad.

Your strategy of getting to a SSH session is likewise not practical. You need a good working install to get SSH working. You are therefore caught in a chicken-or-egg situation. I've already given my thoughts on using Teamviewer to administer a remote box. In general, RDCs (and I would recommend something more robust with Linux than Teamviewer) are great for collaborations, interactive teaching/learning, conferencing, but it's highly inadvisable for administration.

From now on, consider using SSH exclusively for all management tasks, disable passwords and set up rsa key pairs for security, and use either screen or tmux so that a dropped session does not lead to breakage or corruption.

At this point, the best course of action that I can see is to reinstall a pristine system and restore all data from backups. Even chrooting into a broken install is not practical, especially for a general user like your Mom, unfamiliar with the CLI, listening to directions over a hangouts connection across continents.

[Poleh]

I appreciate the response, and will stick to the topic at hand which is looking to solve for the problem. I'll happily get into lectures on my behaviour/life choices/risk posture once she's back online :)

In order of your questions below:

Data is backed up.
Not at all, hence the need to have remote administration tools.
No particular reason, I upgrade her when I go through my own upgrade cycles. Have done so for years.
Nothing odd that we've done to the machine. Vanilla installation, a few apps loaded like TeamViewer and Skype. Certainly no custom file-systems etc.
Battery backup failed - we unfortunately found out the hard way.
We do have another computer, and the LiveUSB option with backup and full re-install is my last resort, and am comfortable managing through that myself.






Is your Mom's important data backed up? That's the first thing I would do if I were her.
How knowledgeable is your Mom? The least painful solution may be to simply have her reinstall, then restore data from backups.
Why are you going to Artful? Is there some Xenial limitation that she can't live with?
What odd things have been done to this machine? btrfs is not part of a default Xenial install. Please list all of your customizations (i.e. additions to/departures from a default install).
Power failures are ubiquitous in some parts of Africa. Is she on battery backup when updating/upgrading? Especially when release-upgrading?
Does your Mom have access to another computer on which she can create a LiveUSB? The idea would be to run a live session and at least be able to backup. This also allows her to chroot into the broken machine.

[DuckHook]

…the topic at hand which is looking to solve for the problem. I'll happily get into lectures on my behaviour/life choices/risk posture once she's back online :)
We deal with lots of new users on these forums who do things a certain way because they drag over old habits from commercial OSes or don't know any better. It looks like you are a power user who knows the risks and have weighed your options. All good then.

Well, the approach I would commonly recommend when things get this bad is to chroot into the broken install, and try to complete the process. But first, it takes a lot of detective work to figure out where the process has stalled/is broken. This depends crucially on when (where in the process) the power failure happened.

Examples:


Is dpkg corrupted? If so, you might be able fo fix it.
Is it just GRUB? Or badly generated initramfs? Then you can try generating new ones.
Corrupted download? Those are tough to fix because you don't know where the problem is.
The worst case is if the new system is only half-installed. You are left with a mix of old, new and missing. Untangling a mess like that is pretty much impossible even if the computer were sitting right in front of you. I wouldn't know where to start on a remote box with a newbie trying to follow command line instructions.


The following is a pretty good short tutorial on chrooting into a failed update/upgrade and trying to complete the process: https://aaronbonner.io/post/21103731114/chroot-into-a-broken-linux-install

Note that a failed update/upgrade is a far cry from a failed do-release-upgrade. However, most attempts to fix things will start from such a chroot environment.