These are the entries from kernel log:
[ 3.453655] iwlwifi 0000:00:14.3: firmware: failed to load
iwlwifi-QuZ-a0-hr-b0-72.ucode (-2)
[ 3.453695] firmware_class: See https://wiki.debian.org/Firmware for
information about missing firmware
[ 3.454449] iwlwifi 0000:00:14.3: firmware: failed to load
iwlwifi-QuZ-a0-hr-b0-72.ucode (-2)
[ 3.454488] iwlwifi 0000:00:14.3: Direct firmware load for
iwlwifi-QuZ-a0-hr-b0-72.ucode failed with error -2
[...]
[ 3.455007] iwlwifi 0000:00:14.3: firmware: failed to load
iwlwifi-QuZ-a0-hr-b0-64.ucode (-2)
[ 3.455902] iwlwifi 0000:00:14.3: firmware: failed to load
iwlwifi-QuZ-a0-hr-b0-64.ucode (-2)
[ 3.458342] iwlwifi 0000:00:14.3: Direct firmware load for
iwlwifi-QuZ-a0-hr-b0-64.ucode failed with error -2
This shows that the kernel tried to load starting from version 72 going
down and failed down to 64. AFAICT the Debian package comes with
version 63 of that firmware, so the above messages were probably followed
by a message indicating success in loading
`iwlwifi-QuZ-a0-hr-b0-63.ucode` (which is why you're able to connect
over wifi ;-)
I'm not sure that these messages correlate to my attempts to log in into the
notebook through SSH.
Very unlikely: the timestamps indicate that these messages were emitted
3.45 seconds after the very beginning of the boot
You might want to try and find version 72 of that firmware, put it into
/lib/firmware/, then do an `rmmod+insmod` (or reboot) to force reloading the
firmware and then see if your problems/delays get solved.