I know it's solved ... but just in case someone is reading this in search of solutions or alternatoves:
I added a fail safe way of installing miniroot image on the pi to be used when the community images are failing.
http://docs.slackware.com/howtos:har...rm:raspberrypi
just keep reading the page down below the links to the community stuff.
Once the miniroot is booting I generally get slackpkg working manually and use that to install all the rest I need. slackware
Slackpkg can install whole package series much like the installer so it's really easy to go from a miniroot to a full system.
On the whole I regard the miniroot thing a really powerful, flexible and fast install method, in fact all my slacware ARM devices are installed starting from a miniroot (thanks Stuart).