Fortunately, I have had a full backup from wednesday, so, after a reflash and KP +backupmenu install, I'm succesfully restored my system.
If I run apt-get update, the faulty (?) updates are reappearing, so I decide not to upgrade this time.
What is this might be? Some repo problem?
Why would this old kernel-version (because it's reflashing an old stock kernel I think) wants to overwrire my KP53?