[quantal] Ubiquity fails to install grub --> no access to Ubuntu after install

[iGor.m]

Firstly, excuse my bad english :)

INITIAL SITUATION:
I was trying to install Ubuntu on an Asus Vintage V7 - P8H61E. But couldn't. Finally I managed installing Fedora 17. There I booted on a LIVE USB with Quantal 64bits (because I wasn't able to boot on a LIVE with any other Ubuntu older than Quantal) and managed to get a boot-info : http://paste.ubuntu.com/1218312
Then I booted again on a LIVE session (legacy-mode) on the same key, and began the installation of Quantal. I went through the manual installation ("Somethingelse") with these partitions :
/, swap and /home.

BUG ENCOUNTERED:
I choose to install the bootloader on /dev/sda1 which is the root partition. The installation went on.
When the install-program was configuring grub-pc, I got this message :
"The grub's installation failed. Sorry, something went wrong. Installing the grub-pc wasn't possible at the indicated place. What do you want to do ? choose another disk where to install the grub-pc ?"
There were different choices : /dev/sda, /dev/sda1 and /dev/sda3
I chose /dev/sda, but got the same error message. The same with /dev/sda3.
The other possibilities were :
To go on without installing any grub
To stop the installation.

I've chosen to go on without the grub. I was warned that I will have to install manually the grub-pc, otherwise it wouldn't be possible to start Ubuntu. I said Ok. The installation went on.

RESULTING SITUATION:
At reboot without liveUSB, no GRUB menu appeared, and no access to Ubuntu.
Then I reboot on a LIVE session, and manage to get another boot-info :
http://paste.ubuntu.com/1218341

WORKAROUND:
Then I started Boot-Repair again from liveUSB, and chose "Recommended repair" (which installed grub-pc into /dev/sda), which succeeded, and provided another boot-info :
http://paste.ubuntu.com/1218343
I rebooted without liveUSB, and succeeded accessing the installed Ubuntu.

FURTHER INFORMATIONS:
Then I tried to install the updates, but the update-manager stopped at "configuring the grub-pc". After a while, I wanted to quit the update-manager, but it didn't quit, it crashed.
I reboot on LIVE session, got another boot-info :
http://paste.ubuntu.com/1218378
I used boot-repair to... repair and get this boot-info :
http://paste.ubuntu.com/1218383

ProblemType: Bug
DistroRelease: Ubuntu 12.10
Package: ubiquity (not installed)
ProcVersionSignature: Ubuntu 3.5.0-15.22-generic 3.5.4
Uname: Linux 3.5.0-15-generic x86_64
ApportVersion: 2.5.2-0ubuntu4
Architecture: amd64
Date: Fri Sep 21 14:14:14 2012
EcryptfsInUse: Yes
InstallCmdLine: noprompt cdrom-detect/try-usb=true file=/cdrom/preseed/ubuntu.seed boot=casper initrd=/casper/initrd.lz quiet splash -- debian-installer/language=fr keyboard-configuration/layoutcode=ch keyboard-configuration/variantcode=fr
InstallationMedia: Ubuntu 12.10 "Quantal Quetzal" - Alpha amd64 (20120920)
SourcePackage: grub-installer
UpgradeStatus: No upgrade log present (probably fresh install)

[iGor.m (igormilhit)]

The original tread about this, on the french ubuntu forum :
http://forum.ubuntu-fr.org/viewtopic.php?pid=10836481#p10836481

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.