Is it possible to upgrade to 12.10 with the downloaded iso file?

[seventhsamurai]

Ok so while it is now concluded that the 800mb iso file cannot be used to upgrade an existing installation of 12.04 keeping all data intact, the pain can be eased a little if you are upgrading on multiple systems.

I ran the upgrade via the internal upgrade tool on 1 system. Once the system was fully upgraded to 12.10, I then ran aptoncd to create an iso file of downloaded packages.

Then I simply restored packages on system no. 2 using aptoncd, which copied most of these upgrade packages onto it. Then I ran the internal upgrade tool, which only asked to download about a 100 files vs the 2000+ files it would have to if you were upgrading from scratch.

[kflorek]

What I do for two systems is to work with the files in

/var/cache/apt/archives

The first system, using say apt, will cache the files into this directory until it has all required. I then copy those to some intermediate media. Then copy the files to the cache directory on the second system (as su of course.) apt checks and uses files in this cache rather then dumbly re-downloading

Something unknown deletes some of these files in later Ubuntus, after a day or so, so don't assume they will be there forever to copy. I wish I knew what. Earlier Ubuntus kept the files permanently, so long as you set it to keep them in synaptic.