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= Summary =

After the Feisty Fawn release, many people have reported various problems that all have the following error in common:

{{{
BusyBox v1.1.3 (Debian 1:1.1.3-2ubuntu3) Built-in shell (ash)
Enter 'help' for a list of built-in commands.

/bin/sh: can't access tty; job control turned off
}}}

What follows is a compendium of fixes and workaround that were gathered on the support channels (with special thanks to the Italian support group).

= Desktop CD (LiveCD) =

The fixes proposed below are valid for those who experience difficulties installing from the Desktop CD or using its 'live' session.

== Kernel Parameters ==

When the boot screen appears, press the `F6` key. A text box will appear, and you should try adding the parameters '''acpi=force''' and '''irqpoll''' to the end of the command line:

{{attachment:desktopcd.png}}

If the '''acpi=force''' parameter doesn't solve your problem, try giving '''acpi=off''' instead.

== Floppy Drive ==

In some cases it's possible for the floppy drive to cause hardware conflicts. In this case, putting a disk in the drive before Ubuntu boots or, alternatively, disabling the floppy from your computer's BIOS interface may help.

= Installed System =

The fixes proposed below are valid for those who experience difficulties using Ubuntu after installing it to the hard drive or upgrading it.

== UUID ==

The partition containing the system's root directory ({{{/}}}) is usually identified by a hexadecimal string called '''UUID'''. This value can be obtained from the file `/etc/fstab`:
{{{
# /dev/sda1
UUID=8d28b051-ed78-412f-9831-4caa49babd04     /     reiserfs     notail     0     1
}}}

If the UUID value indicated there does not match your partition's correct value, it could be changed into the correct value as shown by the command
{{{
blkid
}}}
but it's also worth trying to replace it with the corresponding block device, which can by obtained using the command
{{{
sudo fdisk -l
}}}
since using even the correct UUID is known to generate problems in some cases.

=== Storing GRUB Configuration ===

The appropriate device identifier can be stored to the {{{/boot/grub/menu.lst}}} file, in order to make the GRUB boot loader correctly recognize the root partition during subsequent boots, by changing the '''root''' parameter:
{{{
kernel          /boot/vmlinuz-2.6.20-15-lowlatency root=/dev/sda1 ro quiet splash locale=it_IT
}}}

This change must be performed again after every kernel update or installation. (FIXME: should be added to kopt line!)

=== Temporary GRUB Editing ===

In an emergency, the '''root''' parameter can also be temporarily modified from inside [[Grub|GRUB]] while it is running, allowing to boot into a working system that will later allow permanently modifying `/boot/grub/menu.lst`.

In the kernel list menu, select the entry for the kernel you want to boot from, and hit the «'''e'''» key:

{{attachment:grub1.png}}

In the menu that appears, select the ''kernel'' line and press «'''e'''» again:

{{attachment:grub2.png}}

Then a text edit box will allows you to move to the '''root''' parameter using the cursor keys and substitute the wrong UUID with the correct value:

{{attachment:grub3.png}}

You can confirm your edit by pressing «'''Enter'''», and then hitting the «'''b'''» key to boot your system.

== Initrd ==

It is always best to make sure the ''initial RAM disk'' ('''initrd''') is present after every installation or kernel update. The relevant file should be in the {{{/boot}}} directory, and it is usually named {{{initrc.img-$(uname -r)}}}, where ''$(uname -r)'' is the kernel version.
If it is not found there, it can be generated using the following command:
{{{
sudo update-initramfs -k $(uname -r)
}}}

= Further Troubleshooting =

The above is only a partial collection of solutions for problems related to the "tty" error. In case the proposed fixes didn't help you solve your problem, you should give a detailed report to the community support channels. In particular, the following information will be essential:

 * if the problem manifests itself on the Desktop CD or on an installed system
 * when the problem occurs (immediately after booting begins, after some components have already been loaded, etc)
 * a log of the kernel messages before the error occurred, which can be obtained by loading the system in Safe Graphics Mode (FIXME: how exactly to get to the logs)