EOL upgrade from 7.10 to 8.04, as described in docs, miserably fails

[Teo]

I follow the instructions at https://help.ubuntu.com/community/EOLUpgrades/Gutsy

It doesn't work.
Everything seems to work up to "sudo aptitude update && sudo aptitude safe-upgrade"

But then, after changing the sources.list according to the given instructions, the aptitude update gives errors and the "do-release-upgrades" fails immediately. See the output below.

By the way, it looks like the indicated sources.list is wrong (it is identical to the one that is indicated for the upgrade from 8.04 to 8.10), so I even tried by replacing "hardy" with "gutsy", just in case that was a typo, but the result is the same.

Here's the output I get by following the instructions literally:

$ sudo aptitude update
Ign http://archive.ubuntu.com hardy Release.gpg
Ign http://archive.ubuntu.com hardy/main Translation-en_GB
Ign http://archive.ubuntu.com hardy/restricted Translation-en_GB
Ign http://archive.ubuntu.com hardy/universe Translation-en_GB
Ign http://archive.ubuntu.com hardy/multiverse Translation-en_GB
Ign http://archive.ubuntu.com hardy-updates Release.gpg
Ign http://archive.ubuntu.com hardy-updates/main Translation-en_GB
Ign http://archive.ubuntu.com hardy-updates/restricted Translation-en_GB
Ign http://archive.ubuntu.com hardy-updates/universe Translation-en_GB
Ign http://archive.ubuntu.com hardy-updates/multiverse Translation-en_GB
Ign http://archive.ubuntu.com hardy Release
Ign http://security.ubuntu.com hardy-security Release.gpg
Ign http://security.ubuntu.com hardy-security/main Translation-en_GB
Ign http://security.ubuntu.com hardy-security/restricted Translation-en_GB
Ign http://security.ubuntu.com hardy-security/universe Translation-en_GB
Ign http://security.ubuntu.com hardy-security/multiverse Translation-en_GB
Ign http://archive.ubuntu.com hardy-updates Release
Ign http://archive.ubuntu.com hardy/main Packages
Ign http://archive.ubuntu.com hardy/restricted Packages
Ign http://archive.ubuntu.com hardy/universe Packages
Ign http://archive.ubuntu.com hardy/multiverse Packages
Ign http://security.ubuntu.com hardy-security Release
Ign http://archive.ubuntu.com hardy-updates/main Packages
Ign http://archive.ubuntu.com hardy-updates/restricted Packages
Ign http://archive.ubuntu.com hardy-updates/universe Packages
Ign http://archive.ubuntu.com hardy-updates/multiverse Packages
Err http://archive.ubuntu.com hardy/main Packages
  404 Not Found [IP: 91.189.92.177 80]
Err http://archive.ubuntu.com hardy/restricted Packages
  404 Not Found [IP: 91.189.92.177 80]
Err http://archive.ubuntu.com hardy/universe Packages
  404 Not Found [IP: 91.189.92.177 80]
Ign http://security.ubuntu.com hardy-security/main Packages
Err http://archive.ubuntu.com hardy/multiverse Packages
  404 Not Found [IP: 91.189.92.177 80]
Err http://archive.ubuntu.com hardy-updates/main Packages
  404 Not Found [IP: 91.189.92.177 80]
Err http://archive.ubuntu.com hardy-updates/restricted Packages
  404 Not Found [IP: 91.189.92.177 80]
Err http://archive.ubuntu.com hardy-updates/universe Packages
  404 Not Found [IP: 91.189.92.177 80]
Err http://archive.ubuntu.com hardy-updates/multiverse Packages
  404 Not Found [IP: 91.189.92.177 80]
Ign http://security.ubuntu.com hardy-security/restricted Packages
Ign http://security.ubuntu.com hardy-security/universe Packages
Ign http://security.ubuntu.com hardy-security/multiverse Packages
Err http://security.ubuntu.com hardy-security/main Packages
  404 Not Found [IP: 91.189.91.15 80]
Err http://security.ubuntu.com hardy-security/restricted Packages
  404 Not Found [IP: 91.189.91.15 80]
Err http://security.ubuntu.com hardy-security/universe Packages
  404 Not Found [IP: 91.189.91.15 80]
Err http://security.ubuntu.com hardy-security/multiverse Packages
  404 Not Found [IP: 91.189.91.15 80]
Reading package lists... Done

$ sudo do-release-upgrade
Checking for a new ubuntu release
Failed Upgrade tool signature
Failed Upgrade tool
Done downloading
extracting '/tmp/tmpsKuOQc/hardy.tar.gz'
Failed to extract
Extracting the upgrade failed. There may be a problem with the network or with the server.