I tried adding "/sbin/udevsettle --timeout=10" to the bottom of /usr/share/initramfs-tools/scripts/init-premount/udev, rebuilt my initrd, and it does seem to work on my system just as reliably as the "sleep 10" method.
I tried adding "/sbin/udevsettle --timeout=10" to the bottom of /usr/share/ initramfs- tools/scripts/ init-premount/ udev, rebuilt my initrd, and it does seem to work on my system just as reliably as the "sleep 10" method.