Comment 27 for bug 2065037

You can use systemd-analyze to measure the boot speed. This should be more reliable. For some data, it would be useful to boot three times and average over the boot times (plus calculated deviation). The 5-6 seconds difference is not plausible to me since v4 has a 29 seconds sleep. Could you rerun the v4 test (with only the dhcpcd hostname fix) and v9 with the proposed fix (call dhcpcd with "-K --noipv4ll" and remove the _set_available_devices_to_up call)?

Does the system that freezes without any output succeed in booting eventually? If not, that is worth a separate bug report against initramfs-tools.

Regarding your dmesg question: I don't know.