Edgy -> Fiesty upgrade fails with gzip exception

apt-get update produces the same error, so this isn't an update-manager issue

Purging the contents on /var/lib/apt/lists and /var/lib/apt/lists/partial seems to have unstuck things (making sure that the partial directory remains and the lock file is untouched).

I suspect that all I may have needed to do was trash the file in /var/lib/apt/lists/partial, but it is too late for me to confirm that.

I guess apt should grow some smarts about purging broken files from this area, as it doesn't seem possible to do so without resorting to arcane commands in a root shell.

I get the same problem doing 'apt-get update' on new clean Feisty installation.

Get:10 http://archive.ubuntu.com feisty/universe Packages [4912kB]
57% [10 Packages gzip 0] 56.7kB/s 1m6s
gzip: stdin: not in gzip format
Err http://archive.ubuntu.com feisty/universe Packages
  Sub-process gzip returned an error code (1)
Fetched 1424kB in 1m58s (12.0kB/s)
Failed to fetch http://archive.ubuntu.com/ubuntu/dists/feisty/universe/binary-i386/Packages.gz Sub-process gzip returned an error code (1)
Reading package lists... Done
E: Some index files failed to download, they have been ignored, or old ones used instead.

The file 'archive.ubuntu.com_ubuntu_dists_feisty_universe_binary-i386_Packages' is created in '/var/lib/apt/lists/partial' dir (everytime of the same length of 4911960 bytes). I've purged it and tried again few times, but it didn't help.

[UPD] I downloaded the problematic packages list file, gunzip, rename and move it into '/var/lib/apt/lists' manually, and it works fine. But it is not a way I liked.

Finally, this solution: http://ubuntuforums.org/archive/index.php/t-9944.html (replace 'http://' protocol in the 'sources.list' to 'ftp://') fixed the problem. It seems it's a apt+proxy issue (though I have no idea why the same file is downloaded by wget just fine but corrupted when downloaded by apt)