Pawel Debski's questions

I have a nice and running LUbuntu being booted in EFI by Grub2.

Now I want to chainload Windows 10 from another partition that I copied-over from another disk to the local partition. I want to have it booted directly by winload.efi without intermediary MS-Windows bootmanager BCD hassle.

Here is my /etc-grub.d/40_custom menu:

#!/bin/sh
exec tail -n +3 $0
# This file provides an easy way to add custom menu entries.  Simply type the
# menu entries you want to add after this comment.  Be careful not to change
# the 'exec tail' line above.
menuentry "MS-Windows 10" --class windows --class os {
        insmod chain
        insmod ntfs
        search --no-floppy --set=root --fs-uuid 4E589F8E589F7405
        echo (${root})/Windows/System32/Boot
        ls (${root})/Windows/System32/Boot
        echo (${root})/Windows/System32/Boot/winload.efi
        chainloader /Windows/System32/Boot/winload.efi
}

Unfortunately when I select MS-Windows 10 menu option I get:

(hd0,gpt4)/Windows/System32/Boot
pl-PL/ winload.efi winload.exe winresume.efi winresume.exe
(hd0,gpt4)/Windows/System32/Boot/winload.efi
error: cannot load image.

Press any key to continue...

and Grub cycles.

I am pretty sure that winload.efi is there, since when I drop to Grub2 command line and manually do

insmod ntfs
ls (hd0,gpt4)/Windows/System32/Boot

the files are there.

I think that winload.efi needs some arguments like C:\Windows or something similar that Windows Boot Manager takes from BCD and passes to winload.

1. What are the exact options to winload?
2. How to make it load Windows?

I have a pretty small Ubuntu 20 LTE install. It is essential that it is small, however fully functional with LibreOffice, Thunderbird, etc.

I have noticed recently that /home/me/.local/share/flatpak uses nearly 1 GB of data, however I have no Flatpak apps installed:

$ pwd
/home/me/.local/share/flatpak/repo/objects
$ du -s *
112 00
92  01
108 02
12696   03
44  04
92  05
28  06
184 07
96  08
11680   09
48  0a
180 0b
68  0c
108 0d
136 0e
96  0f
11548   10
76  11
64  12
160 13
12156   14
72  15
100 16
80  17
11580   18
80  19
92  1a
56  1b
13036   1c
116 1d
56  1e
92  1f
64  20
76  21
84  22
52  23
96  24
52  25
60  26
72  27
11628   28
11364   29
32  2a
188 2b
100 2c
12972   2d
52  2e
160 2f
120 30
104 31
88  32
108 33
25364   34
108 35
96  36
96  37
124 38
32  39
92  3a
116 3b
56  3c
76  3d
184 3e
12892   3f
180 40
120 41
160 42
108 43
13040   44
11700   45
124 46
56  47
88  48
48  49
168 4a
128 4b
11904   4c
20  4d
164 4e
72  4f
108 50
11676   51
11264   52
32  53
80  54
84  55
48  56
56  57
124 58
64  59
68  5a
11852   5b
40  5c
56  5d
60  5e
84  5f
11344   60
108 61
68  62
64  63
25080   64
152 65
36  66
80  67
88  68
60  69
200 6a
24  6b
72  6c
176 6d
52  6e
120 6f
13048   70
12208   71
11612   72
48  73
44  74
44  75
13044   76
96  77
124 78
132 79
96  7a
108 7b
132 7c
11416   7d
80  7e
64  7f
112 80
72  81
64  82
52  83
124 84
160 85
36  86
11360   87
172 88
92  89
12684   8a
76  8b
72  8c
116 8d
80  8e
68  8f
116 90
132 91
96  92
92  93
68  94
76  95
52  96
80  97
164 98
120 99
48  9a
11932   9b
56  9c
11616   9d
72  9e
80  9f
84  a0
108 a1
11252   a2
92  a3
60  a4
88  a5
36440   a6
56  a7
12004   a8
12192   a9
72  aa
60  ab
84  ac
48  ad
108 ae
40  af
48  b0
56  b1
44  b2
44  b3
11700   b4
11420   b5
24  b6
11344   b7
88  b8
64  b9
56  ba
56  bb
56  bc
36  bd
116 be
68  bf
160 c0
48  c1
48  c2
56  c3
32  c4
12056   c5
44  c6
128 c7
124 c8
76  c9
12044   ca
84  cb
13072   cc
176 cd
128 ce
76  cf
152 d0
160 d1
96  d2
172 d3
88  d4
124 d5
116 d6
80  d7
96  d8
100 d9
164 da
76  db
76  dc
48  dd
60  de
88  df
60  e0
128 e1
76  e2
48  e3
68  e4
92  e5
48  e6
100 e7
40  e8
56  e9
13184   ea
60  eb
32  ec
12760   ed
13008   ee
11552   ef
64  f0
164 f1
36220   f2
12884   f3
136 f4
11704   f5
32  f6
13004   f7
112 f8
12996   f9
144 fa
11652   fb
12936   fc
144 fd
116 fe
48  ff
$ flatpak list
$ 

If so what is stored there and how to safely remove its content?

I have the default Ubuntu 20.04 LTS kernel installed which is currently

$ uname -r
5.4.0-7634-generic

I'd like however to install older kernel version of 5.3. I do see a package linux-image-5.3.0-7648-generic but when I try to install it Synaptic cannot find the actual package.

Do I miss some repo in /etc/apt ?

What would it be the easiest way to use 5.3 kernel and have it automagically upgraded whenever Canonical releases new 5.3.x version?

I'd like to use Remmina client to connect to Windows Server on remote location. The provider supplied me with a client certificate and an RDP file.

When I click the RDP file Remmina not surprisingly vents its anger on me with "Authentication failed" message.

How can I use client CER certificate for the authentication in Remmina?

I have a small internal SDD drive with Ubuntu and I often run-out of /tmp space. I am going to add another, large HDD. It is critical for me that /tmp is as fast as possible not to impact performance of my key applications. What is better from the performance point of view: * create a partition on external drive and mount it over internal /tmp, or * move some data to make more space in internal /tmp

When I insert audio CD I get the following message:

Unable to mount Audio Disk Message recipient disconnected from messages bus without replying

When I start Sound Juicer the following message appears:

Could not read the CD Sound Juicer could not read the track listing on this CD. Reason: Cannot access CD: The specified location is not mounted

For your info:

• VLC can play the CD by selecting "Audio CD" and /dev/sr0, but the playback stops a few times and after a while computer hangs and hard reset is required (even ctrl-alt-F1 does not work)
• the CD is not visible in Rhythmbox
• other music CDs can be played and extracted with Sound Juicer on this machine without any problem
• the CD I insert plays music in car CD drive without any problem
• also Mac can play this CD and import it into iTunes, so I am sure physical media is ok

However when I insert various CDs into this machine I am getting following errors on console 1 (Shift-Alt-1):

I have gvfs-backends installed:

$ apt list --installed | grep gvfs

WARNING: apt does not have a stable CLI interface. Use with caution in scripts.

gvfs/xenial-updates,now 1.28.2-1ubuntu1~16.04.2 amd64 [installed]
gvfs-backends/xenial-updates,now 1.28.2-1ubuntu1~16.04.2 amd64 [installed]
gvfs-bin/xenial-updates,now 1.28.2-1ubuntu1~16.04.2 amd64 [installed]
gvfs-common/xenial-updates,xenial-updates,now 1.28.2-1ubuntu1~16.04.2 all [installed]
gvfs-daemons/xenial-updates,now 1.28.2-1ubuntu1~16.04.2 amd64 [installed]
gvfs-fuse/xenial-updates,now 1.28.2-1ubuntu1~16.04.2 amd64 [installed]
gvfs-libs/xenial-updates,now 1.28.2-1ubuntu1~16.04.2 amd64 [installed]

I also did the cdrom group correction as suggested by the answer below:

$ ls -l /dev/cdrom /dev/sr0
lrwxrwxrwx  1 root root      3 lip  9 21:53 /dev/cdrom -> sr0
brw-rw----+ 1 root cdrom 11, 0 lip  9 21:53 /dev/sr0
$ cat /etc/group | grep cdr
cdrom:x:24:someadmin
$ sudo adduser myuser cdrom
[sudo] password for myuser: 
Adding user `myuser' to group `cdrom' ...
Adding user myuser to group cdrom
Done.
$ cat /etc/group | grep cdr
cdrom:x:24:someadmin,myuser
...reboot...
$ id
uid=1001(myuser) gid=1001(myuser) groups=1001(myuser),24(cdrom),129(vboxusers),999(docker),1002(xcryptusers)

and the problem unfortunately persists.

I am planning a few videoconferences and I want to check if everything works ok. What is the easiest way to check my Ubuntu installation if it works with Google Hangouts?

The best would be some robot that I can call that plays back my message with some delay. Is there a service like that?

If not, can you suggest any small app that uses webcam & microphone to record a message and play it back.

I am pretty much used to Windows Key + L shortcut to lock the screen. Ubuntu has a nice config app to change key bindings. Unfortunately I could not find similar app in Lubuntu.

How can I change key-bindings in Lubuntu?

I have a SIM card with huge data package. Can I use my Android phone to connect my Ubuntu PC to the Internet?

When I format a drive to NTFS under Windows and plug it into the Ubuntu machine, it is perfectly usable. But when I format it under Ubuntu using Disks (delete all partitions and create one single partition with NTFS), it does not show up when plugged into the Windows machine.

Please note that in both cases the USB drive contains only one, primary partition formatted to NTFS, for example:

• /dev/sdb - the actual device
• /dev/sdb1 - the only, primary partition

I've observed this behaviour both with a solid state USB pen-drive, as well as with an external USB magnetic HDD.

How to (re)format a USB HDD or a stick to NTFS under Ubuntu so it is usable under Windows?

Can you please direct me to some examples and more detailed instruction on /etc/sudoers.d/

I'd like to give some group permission to sudo some commands, but in a proper way not to create unnecessary loopholes in the Ubuntu security model on a multi-user machine.

In ancient times I did some simple sudoers customisations, but apparently now /etc/sudoers.d/ is a more proper way and I'd like to better understand it.

I have a number of external media with VeraCrypt encrypted file containers and I would like the users to mount and use them without giving root privileges to the users.

However at the moment VeraCrypt's always asking for user/admin password apparently sudo-ing mount operation:

How can a user, who's not in the sudoers file mount an .hc file?

I have a number of encrypted volumes on external media encrypted either with TrueCrypt or VeraCrypt. What is the recommended way to install and use VeraCrypt under Ubuntu?

I have the problem described here: How to solve bleaching Krusader? and I want to reset Krusader configuration to fresh-install-like one. (unfortunately opening configuration and applying defaults does not help)

1. How can I completely reset Krusader configuration to fresh-install-like one (preferably) or
2. Remove Krusader config file (what's the name and where's it located?)

I tried to remove configuration files as described here: https://docs.kde.org/trunk5/en/extragear-utils/krusader/config_files.html but:

$ qtpaths --paths GenericDataLocation
qtpaths: could not find a Qt installation of ''

And no such files exist:

~/.config/krusaderrc
~/.local/share/kxmlgui5/krusader/krusaderui.rc

I do not believe that global config is screwed as this user has no access there nor this user is in sudoers list.

One important thing to mention is that when I start Krusader from terminal the following error message is printed:

$ krusader
krusader(6646)/kdecore (KLibrary) findLibraryInternal: plugins should not have a 'lib' prefix: "libkonsolepart.so"

So it looks like there is some package conflict - before I had installed some other utilities krusader had worked as expected. See the exact description in linked question (bleaching Krusader).

I have installed Tor Browser Launcher:

sudo apt-get install torbrowser-launcher

but when I try to run Tor Browser the download always fail:

Note: other downloads finish properly and I can correctly verify signatures, so apparently there is problem with Tor Browser download rather than attack on the system.

For your info here is Tor Browser Launcher config:

I particularly like the feature of Total Commander, that while moving or copying files it can verify whether the files were actually correctly copied and the copies match. Here is the list of Total Commander alternatives: https://168hours.wordpress.com/2008/08/18/10-total-commander-alternatives-for-linux/ so I decided to give mc (Midnight Commander) a try, partially that I used it in my Xenix times - who remembers Xenix, the Microsoft Unix, now?

Much to my astonishment mc does not an option to automatically compare copied files.

Which one of the other file managers has an option to compare copied/moved files automatically?

I can hear no sound in the speakers. When I attach headphones the sound is heard correctly. alsmixer shows no clues:

(when I attach headphones speaker gets muted and sound-bar of headphones goes up to 100 - visible in real-time)

Again pavucontrol - Ubuntu volume control - seems OK:

(when I attach headphones port changes to "Headphones (plugged in)" - visible in real-time and I hear the sound via headphones as expected)

There is one thing interesting in gnome-alsamixer though. However I have no idea how to rectify it. When launched from terminal it prints the following errors:

    pdebski@PaDeLT430s:~$ gnome-alsamixer

    ** (gnome-alsamixer:24782): WARNING **: gam_toggle_get_state (). No idea what to do for mixer element "Auto-Mute Mode"!

    ** (gnome-alsamixer:24782): WARNING **:         gam_toggle_get_state (). No idea what to do for mixer element "Loopback Mixing"!

    (gnome-alsamixer:24782): GLib-CRITICAL **: Source ID 71 was not found when attempting to remove it

and shows speaker muted:

However un-muting speaker and sliding it to top does not help. Same for "Internal". Note that when I close and reopen gnome-alsamixer both Speaker and Internal sliders stay at the top position but no sound from internal speakers is heard.

What else can I do to hear the sound in the speakers?

My Ubuntu live USB hangs on boot. I suspect a driver is causing the hang. How can I identify which driver actually causes the freeze?

Here are the details:

1. During boot I press F12 and select USB storage, when Ubuntu screen shows I select "try before installing" and the screen goes blank with blinking cursor in the left-top corner. Neither ctrl-alt-del nor power-off works. I need to hard power off the machine by holding the power button.
2. During boot I press F12 and select USB storage, when Ubuntu screen shows I press F6 and mark acpi=off, noapic, edd=on, nodmraid and nomodeset options, then I edit boot line by removing quiet splash and adding no_console_suspend initcall_debug options and press enter. Ubuntu boots but at certain point hangs with kernel panic messages. Neither ctrl-alt-del nor power-off works. I need to hard power off the machine by keeping power-off button for a few seconds.

Here is a screenshot:

Is there any way I can identify which drivers that are being loaded to tell which driver causes the hang and possibly disable it?

I have a laptop with a faulty touchscreen. It is most likely why I get kernel panic during the boot.

How can I disable the touchscreen during the boot?