Created attachment 409810 [details]
reproducer for the buggy urlgrabber
When the urlopen() method is used it doesn't return the parsed HTTP headers in the hdr property created by the _return_hdr_obj() method. This is in my opinion the real cause for the preupgrade issues with small /boot partitions on F-12.
fixed in upstream -
not yes pushed into a pkg.
pushed into pkgs for f12 and f13 in koji - not pushed to stable for either, yet.