I was able to get it booting with the minirootfs from the manual method
http://docs.slackware.com/howtos:har...rm:raspberrypi
This is how I got my 3 working back in March (before the fatdog installer was released for the 3) and the BeagleBone a while back.
The manual method takes a bit of work but you can break it down into separate sections. I download the Raspbianmini and then make the raspbian_boot_files like the doc says and then I extract it to a folder. You only have to do that once for all your Pi's (or any time they update).
Then prep your sd card, extract the minirootfs to it and then copy the contents of the three folders under raspbian_boot_stuff over and edit the config a bit (fstab, keyboard map and I go ahead and chmod +x rc.ntpd and edit its config file as well as copy over slackpkg).
It took a couple tries when I first did it on the BBB and I think I had to do it twice for the RP3 as I must have missed a step somewhere but worked the first time with the zero.
Please excuse the grainy picture as I had the lights down low after the rest of the family went to bed and I don't have any computer monitors so I have to use the TV as its the only thing with HDMI in but here is Slackware ARM Current miniroot fs on the Pi zero.
http://i306.photobucket.com/albums/n...c/KIMG0252.jpg