Locking down Grub with a password is a great idea,
but sometimes things go wrong and you might find yourself locked out from booting your computer.
The following example is from memory so I may have missed a step, but it should be close to how to fix this issue

Boot into a live Linux CD or USB
(Note: I have found it needs to be the same version of Linux, especially when using the newer versions of Ubuntu.)

Start a terminal session
Type: sudo fdisk -l
Find the boot partition of you linux installation (In this example we have it install on /dev/sda1)

sudo mount /dev/sda1 /mnt

Remove you changes in /mnt/etc/grub.d/00_header (or whichever grub configuration file you changed that caused the issue

Create some neccessary hardlinks
sudo mount –bind /dev /mnt/dev
sudo mount –bind /proc /mnt/proc
sudo mount –bind /sys /mnt/sys
sudo chroot /mnt
update-grub /dev/sda1
CTRL-D
sudo umount /mnt/dev
sudo umount /mnt/proc
sudo umount /mnt/sys
sudo umount /mnt

When using the wifi option WPA & WPA2 Enterprise with PEAP and no CA certificates, later versions of Ubuntu are failing to connect even though you tell it not to use a certificate and to ignore.
To fix this do the following:

In /etc/NetworkManager/system-connections/”connection-name”

remove: “system-ca-cert=true"

Ubuntu seems to currently (6/24/2014) have issues with the atheros bluetooth card.

Best fix so far:

I created a file [bluetooth-fix.conf] under /etc/modprobe.d with this line:
options ath9k btcoex_enable=1

Enabling bluetooth coexistence

Reboot


Also:

Bluetooth coexistence has to be manually enabled when loading ath9k by setting the btcoex_enable module parameter.

modprobe ath9k btcoex_enable=1

By: F Alduraibi

At this point resizing a Virtualbox disk image is done from the command line.

* This page assume you have already detached the virtual disk from your virtual machine

To turn a Windows.vdi from a 25 GB drive to a 30 GB drive

1. Start a terminal session
2. change directory to the directory your virtual disk is stored in
3. Enter: VBoxManage modifyhd Windows.vdi –resize 30720

VBoxManage modifyhd virtualdrivename –resize Megabytes

To reattach your virtual disk to a Virtual machine called Windows

1. Start a terminal session
2. change directory to the directory your virtual disk is stored in
3. Enter: VBoxManage storageattach Windows –storagectl “SATA” –device 0 –port 0 –type hdd –medium Windows.vdi

Udisks and udev are related. Normally, as you can see from the above examples, when a new USB stick or DVD inserted, it is automatically mounted and the file manager is displayed. Suppose, instead, that you want that USB stick or DVD to be ignored and not mounted. How would you configure your system to do this?

While researching how to disable the automatic mounting of devices for a Linux kiosk project I was working on, I spent a number of hours on the Internet reading purported solutions to the problem. The majority of the solutions (probably 99%) simply did not work because the solution referred to obsolete versions of udev, HAL (Hardware Abstraction Layer), DBus or solutions based on PolicyKit or gsettings.

The simplest method that I have found is to create a low numbered file (I call mine 10-local.rules in /etc/udev/rules.d containing the following rule:

ACTION=="add|change", SUBSYSTEM=="block", KERNEL=="sd*|sr", ENV{UDISKS_PRESENTATION_HIDE}="1"

A twist on the above rule would apply to a kiosk-like LiveCD containing a persistent data partition to restrict mounting to /dev/sda*:

ACTION=="add|change", SUBSYSTEM=="block", KERNEL=="sd[b-e]*|sr", ENV{UDISKS_PRESENTATION_HIDE}="1"

By: Zurlinux