As the latest release of Ubuntu has been out for a little while now – I decided to upgrade my laptop OS from 8.04 to 8.10. Ubuntu has the really nice facility of upgrading the OS in place – just by clicking the upgrade button. It was really nice to use when I upgraded from 7.10 on another PC. This time there was a problem.
There were various errors including “BADSIG 40976EAF437D05B5” and “Hash Sum mismatch” on the various Ubuntu repositories. I tried a number of fixes found via Google, mostly to no avail. Eventually I found an article in a forum pointing to a proxy server caching issue.
The fix that worked for me was as follows.
I added the following two lines...
to the file /etc/apt/apt.conf.d/10broken_proxy. This file did not previously exist on my system – but is referenced if it exists (as I found out due to a typo :-) ).
And separately did this....
sudo cp /etc/apt/sources.list /etc/apt/sources.list_backup
sudo nano /etc/apt/sources.list (then delete all the contents)
sudo apt-get update
Then replace the empty sources.list with the sources.list_backup – effectively putting all the original contents back into the sources.list file.
Run "sudo apt-get update” again.
My system could access the repositories perfectly. Finally I upgraded the system by running “Sudo do-release-upgrade -m desktop”.
All went well and now Ubuntu is running version 8.10.
Thanks to Asiyu on the Ubuntu forums