Unless I messed up somewhere, the tgz file I got out of kindle_update_tool.py was missing a proper tar/gz header, and didn't match the md5sum.
I had to fiddle with it a bit to be able to uncompress it.
I'm somewhat befuddled to find out that they're still trying to use a -rt kernel (2.6.31-rt11)... Will it end up being built without preempt at all, like they did with the K3? Because that was funny, watching them switch gradually from PREEMPT_RT to PREEMPT_NONE... ;p. On the other hand, glad to see that it's running on an A8!
And, yay, looks like there's a I18N UI in there