This patch to "/usr/share/initramfs-tools/scripts/local-premount/mdadm" solves the issue for me.
** Patch added: "mdadm.patch" https://bugs.launchpad.net/ubuntu/+source/update-manager/+bug/942106/+attachment/3132597/+files/mdadm.patch ** Tags added: oneiric precise -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/942106 Title: mdadm-functions missing udevadm settle (?) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/mdadm/+bug/942106/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs