OK, I got through the update, but got the following error messages at the end:

warning: rpmts_HdrFromFdno: V3 DSA signature: NOKEY, key ID 1ac70ce6
public key not available for //var/cache/yum/extras/packages/ppracer-0.3.1-4.fc4.1.i386.rpm
public key not available for //var/cache/yum/extras/packages/lapack-3.0-37.fc4.i386.rpm
public key not available for //var/cache/yum/extras/packages/cdlabelgen-3.5.0-1.fc4.noarch.rpm
public key not available for //var/cache/yum/extras/packages/SDL_image-1.2.4-1.fc4.i386.rpm
public key not available for //var/cache/yum/extras/packages/gnet2-2.0.7-5.fc4.i386.rpm
public key not available for //var/cache/yum/extras/packages/bzflag-2.0.8-1.fc4.i386.rpm
public key not available for //var/cache/yum/extras/packages/Maelstrom-3.0.6-8.i386.rpm
public key not available for //var/cache/yum/extras/packages/SDL_mixer-devel-1.2.6-3.fc4.i386.rpm
public key not available for //var/cache/yum/extras/packages/SDL_image-devel-1.2.4-1.fc4.i386.rpm
public key not available for //var/cache/yum/extras/packages/pan-0.14.2.91-3.1.fc4.i386.rpm
public key not available for //var/cache/yum/extras/packages/splint-3.1.1-13.fc4.i386.rpm
public key not available for //var/cache/yum/extras/packages/octave-2.9.5-1.fc4.i386.rpm
public key not available for //var/cache/yum/extras/packages/SDL_net-devel-1.2.5-5.i386.rpm
public key not available for //var/cache/yum/extras/packages/freeciv-2.0.8-1.fc4.i386.rpm
public key not available for //var/cache/yum/extras/packages/SDL_mixer-1.2.6-3.fc4.i386.rpm
public key not available for //var/cache/yum/extras/packages/blas-3.0-37.fc4.i386.rpm
public key not available for //var/cache/yum/extras/packages/SDL_net-1.2.5-5.i386.rpm
public key not available for //var/cache/yum/extras/packages/c-ares-1.3.0-2.fc4.i386.rpm
public key not available for //var/cache/yum/extras/packages/hdf5-1.6.5-4.fc4.i386.rpm
public key not available for //var/cache/yum/extras/packages/fftw-3.1-3.fc4.i386.rpm
public key not available for //var/cache/yum/extras/packages/ufsparse-1.2-1.fc4.i386.rpm

The FAQ described what to do:
>blockquote>Edit /etc/yum.repos.d/fedora.repo and replace the line
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-fedora
with:
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY
Which I did, but no joy.
What now?

Rand, your comment filters find my comments objectionable, so I'm sending it by e-mail. Hopefuly those filters are not in league with these filters...

OH, and way to go me, I spent so much energy proving that it's the Extras' key, when the repo name "extras" is encoded in the cache pathname. My powers of hindsight are unsurpassed.

Basically, the solution MAY BE:
- undo edits to fedora.repo
- download Extras key if not present
- edit fedora-extras.repo to point to right key

Hindsight keeps coming. The procedure (from Wiki) opens with an installation of fedora-release-4-2. It that was done, there's no way for Extras' key to be missing, so everything I wrote is nonsense, unfounded.

Restarting the fault tree, I see two explanations:
a) Someone signed packages with a key other than Extras (but it's a valid key, see... Ergo, an employee of Red Hat mixed it up by using Red Hat key instead of Extras),
b) There was a key change, but some mirrors retain old packages
c) Something else happened

This seems to trend toward gpgcheck=0. Although first we have to make sure the /etc/pki checks out, no files missing or corrupt ("rpm -V fedora-release" would do). Also, check that fedora-extras.repo points to correct key.

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