## ChromeOS Upgrade from Debian 9 to Debian 10 – aka Buster – Google Script crashed.

I have one of those Chromebooks, which allow a Linux subsystem to be installed, that subsystem being referred to in the Google world as “Crostini”. It takes the form of a Virtual Machine, which mounts a Container. That container provides the logical hard drive of the VM’s Guest System. What Google had done at some point in the past was, to install Debian 9 / Stretch as the Linux version, in a simplified, automated way. But, because Debian Stretch is being replaced by Debian 10 / Buster, the option also exists, to upgrade the Linux Guest System to Buster. Only, while the option to do so manually was always available to knowledgeable users, with the recent Update of ChromeOS, Google insists that the user perform the upgrade, and provides ‘an easy script’ to do so. The user is prompted to click on something in his ChromeOS settings panel.

What happened to me, and what may also happen to my readers is, that this script crashes, and leaves the user with a ChromeOS window, that has a big red symbol displayed, to indicate that the upgrade failed. I failed to take a screen-shot of what this looks like. The button to offer the upgrade again, is thankfully taken away at that point. But, if he or she reaches that point, the user will need to decide what to do next, out of essentially two options:

• Delete the Linux Container, and set up a new one from scratch. In that case, everything that was installed to, or stored within Linux will be lost. Or,
• Try to complete the upgrade in spite of the failed script.

I chose to do the latter. The Linux O/S has its own method of performing such an upgrade. I would estimate that the reason for which the script crashed on me, might have been Google’s Expectation that my Linux Guest System might have 200-300 packages installed, when in fact I have a much more complete Linux system, with over 1000 packages installed, including services and other packages that ask for configuration options. At some point, the Google Script hangs, because the Linux O/S is asking an unexpected question. Also, while the easy button has a check-mark checked by default, to back up the Guest System’s files before performing the upgrade, I intentionally unchecked that, simply over the knowledge that I do not have sufficient storage on the Chromebook, to back up the Guest System.

I proceeded on the assumption, that what the Google script did first was, to change the contents of the file ‘/etc/apt/sources.list’, as well as of the directory ‘/etc/apt/sources.list.d’, to specify the new software sources, associated with Debian Buster as opposed to Debian Stretch. At that point, the Google script should also have set up, whatever it is that makes Crostini different from stock Linux. Only, once in the middle of the upgrade that follows, the Google script hanged.

(Updated 10/25/2020, 22h55… )

## Whether it would be fair to expect, that the Debian libc6-dev package work, on an ARM-64 CPU-based device.

One of the facts which I had posted about before was, that I had installed Debian 10 / Buster on a Google Pixel C Tablet, not because that tablet has any special properties, but just to document that with that one specific configuration, the solution ‘works’. And I had gotten to the subject of wanting to install ‘libc6-dev’, which would normally install Development Libraries, on top of Run-Time Libraries, with the ultimate intention of being able to compile or custom-compile C or C++, from in front of this ARM-64 -CPU Device, for use on the same device. And even one major Debian Update later, from 10.0 to 10.1, this facility still doesn’t work.

What I’d like to comment is the idea, that this is not a fair expectation, and that the naming of these packages cannot always be expected to remain canonical. What this expectation would assume is that the general-purpose GNU Compiler will work, even though that compiler is highly optimized for targeting code that runs, either on ‘amd64′ or ‘i386′ architecture, in that order.

If the goal really was, to compile code from in front of an ARM-64 -based machine, to run on it, then a compiler would need to be selected which is meant to target the ARM-64 CPU, and this might involve installing the correct cross-compiler, even though it’s to be executed on an ARM-64. The fact that an ARM-64 version of ‘libc6-dev’ is available, really just stems from the rather nonsensical idea, that the compiler using it should run on an ARM-64, but that the linked code should not.

And then, if one has installed the correct cross-compilers, because those packages are available in ‘arm64′ versions, they will run in spite of being named cross-compilers, and then installing them will also pull in the correct development libraries. Only then, in order actually to compile anything, one would need to specify yay-long commands from the command-line. And the main reason I’ll have none of this, is the simple fact that entering many non-standard ASCII characters using an Android-oriented keyboard, does not appeal to me for the moment.

This is similar to why I don’t install ‘Web-development software’, that is compiled and available from the repositories, but that would require a long sequence of special characters to be typed in, in order to allow any sort of Web-development. And it remains consistent with having LibreOffice installed, where what gets typed, is consistent with the English language, just as what the Google Pixel C’s OEM Keyboard offers, is…

There’s an added level of weirdness that would result, if somebody was just to write and compile C or C++ to run on an ARM-64 CPU in that way: The resulting binary wouldn’t be Android-compatible. It would assume that the O/S is Linux, but with an ARM-64 CPU, just like the Guest System. Writing Android-compatible code would require, that the ‘Android Development Kit’ be installed. Due to cross-compiling by the Debian package maintainers, there just might be ‘arm64′ packages of that available, but again, with no further guarantee that it all works…

(Update 9/08/2019, 10h20 : )

Unfortunately, this recognition does not negate the fact, that the way certain packages have been compiled to run on an ARM-64 CPU, still contain a bug…

## Major Problem when Upgrading a UserLAnd Linux Guest System via ‘apt-get’.

A fact which I had blogged about before was, that I had installed a Debian 10 Linux Guest System on the Android, Google Pixel C Tablet, using the Android app ‘UserLAnd’. This Debian 10 version was compiled by the package maintainers to run on an ARM-64 CPU.

Well, along with major updates to Debian 9 / Stretch, the Debian maintainers have just issued an update to Debian 10 / Buster, from version 10.0 to version 10.1 . The problem? When trying to perform the upgrade via ‘sudo apt-get’, the process hangs over the attempt to update or install ‘systemd’, and then configure it. Apparently, doing this requires full root privileges, because ‘systemd’ would normally control how services run in the background with ‘root’, but UserLAnd does not allow any part of its Guest System to run as ‘root’.

This could become a stumbling-block, in any future updates.

The ‘solution’ which I attempted to apply was, to remove everything that depends on ‘systemd’, and to re-apply the upgrade in total. But the net effect of that is, to remove many more packages than I intended to remove, including all things related to ‘Gtk 3′, ‘LXTerminal’, as well as key components that allow ‘LXDE’, the Lightweight Desktop Manager, to function at all.

Caution: This would have been a completely unsafe thing to do on a real computer, and was only plausible because the setup in question was virtual in some way, and also expendable. This would normally brick the computer…

When the makers of UserLAnd provided easy screen-shortcuts to install Debian and LXDE, they knew how to modify the installation script, to ignore whatever problems result from installing LXDE and its dependencies in a ‘proot’ed environment. But I don’t know those tricks. (:1) So at one point I had a partially gutted system, without LXDE really installed.

But the (Android) devs behind UserLAnd also provided a quick workaround for that problem. The next time I exited the corrupted session, and re-launched LXDE from the UserLAnd menu, this Android app recognized that LXDE was no longer installed, and simply reinstalled it for me, after which I could access it again.

Once I had done this, my wallpaper was a black background, and quite a few of the installed applications were no longer installed. And so what I needed to do next was, to run the equivalent of the following command:


\$ sudo apt-get install gnome-backgrounds clipit evince wxmaxima gcl firefox-esr libpam-cracklib



After having done this, I was able to select a wallpaper again, from the file chooser, and to regain most of the abilities I already had before.

I might still be missing some of the applications I once had.

But what all this suggests is, that the Linux Guest System should only consist of a vest-pocket system, with a small number of applications, because in reality any and all Linux applications may simply need to be reinstalled at some point in time. But, there is a way in which users are not ‘hosed’ if this happens:

Linux still segregates its data into a system directory, and a user home directory. Even though we have no form of access control within a ‘proot’ed system, even if certain applications are removed from the system directory, and then reinstalled there, our home directory will remember all our personal settings and data.

So the solution can be as quick as the initial disaster was.

My Linux Guest System is now down to taking up 4.86GB of Android application-data.

(Updated 9/09/2019, 16h15 … )

(As of 9/07/2019, 20h00 : )

I think I’ve gotten closer to finding out, what went wrong…