> > linux-firmware-nonfree package, in case you don't have this installed.
Do you have this package installed? What does "apt-cache policy
linux-firmware-nonfree" say?
> deb cdrom:[Debian GNU/Linux testing _Stretch_ - Official Snapshot amd64 DVD
> Binary-1 20150518-05:37]/ stretch contrib main
You can comment this one out. Also, the lines for Jessie might as well
be removed so you don't accidentally uncomment them at some point. Keep
a backup of the whole file if you want to keep a record of them.
> Does the above look OK or is it a bit addled in some way?
It looks OK, I don't think your problem has anything to do with this.
If you install the package "bootlogd" you will get a file
called /var/log/boot.log after your next boot with all boot messages.
You might want to remove "quiet" from the line with
GRUB_CMDLINE_LINUX_DEFAULT in /etc/default/grub and run update-grub to
see messages during boot.
Also, what does "cat /proc/cmdline" say?
Petter
--
"I'm ionized"
"Are you sure?"
"I'm positive."