I don't think the edit of /lib/udev/rules.d/97-bluetooth-hid2hci.rules is a complete solution.
I filed a new bug https://bugs.launchpad.net/ubuntu/+source/initramfs-tools/+bug/1165579 with more information.
The init of the unifying receiver works intermittently, regardless of the /lib/udev/rules.d/97-bluetooth-hid2hci.rules edit (I've tried with both, reboots inbetween). It's possible it works more often with the edit in place.
I don't think the edit of /lib/udev/ rules.d/ 97-bluetooth- hid2hci. rules is a complete solution.
I filed a new bug https:/ /bugs.launchpad .net/ubuntu/ +source/ initramfs- tools/+ bug/1165579 with more information. rules.d/ 97-bluetooth- hid2hci. rules edit (I've tried with both, reboots inbetween). It's possible it works more often with the edit in place.
The init of the unifying receiver works intermittently, regardless of the /lib/udev/