OK. Towards my usual ugrade, I'm told:

Setting up libbasicusageenvironment1:amd64 (2016.11.28-1+deb9u2) ...
Setting up mariadb-client-core-10.1 (10.1.38-0+deb9u1) ...
Setting up grub-pc (2.02~beta3-5+deb9u1) ...
Installing for i386-pc platform.
grub-install: error: cannot write to `/dev/sdb': Input/output error.
Installing for i386-pc platform.
Installation finished. No error reported.
Installing for i386-pc platform.
grub-install: error: cannot write to `/dev/sdb': Input/output error.
Installing for i386-pc platform.
Installation finished. No error reported.
Installing for i386-pc platform.
grub-install: warning: this GPT partition label contains no BIOS Boot Partition; embedding won't be possible.
grub-install: error: embedding is not possible, but this is required for RAID and LVM install.

(and that's where it seems to have stalled)

By the way, each time it told me "Installation finished. No error reported" it had actually complained it could not install on /dev/sdb

At this point, it has failed to write to /dev/sdb twice, presumably because I have only one hard drive. When it fails the second time and tries again I tell it to insatall to dev/sda which does exist. It now complains about my GPT partition label. I don't have a GPT partition label. My machine is a bios machine. See:

root@midwinter:~# fdisk -l /dev/sda
Disk /dev/sda: 111.8 GiB, 120034123776 bytes, 234441648 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0x1c229ec6

Device     Boot     Start       End   Sectors  Size Id Type
/dev/sda1            2048   1953791   1951744  953M 83 Linux
/dev/sda2  *      1953792   3907583   1953792  954M 83 Linux
/dev/sda3         3907584 119173119 115265536   55G 8e Linux LVM
/dev/sda4       119175166 234440703 115265538   55G  5 Extended
/dev/sda5       119175168 121126911   1951744  953M 82 Linux swap / Solaris
/dev/sda6       121128960 141608959  20480000  9.8G 83 Linux
root@midwinter:~#

What gives?

At this poiit I'm afraid to turn my machine off, lest it never start again.

The machine is a Purism laptop, running Devuan beowulf. Oddly, when
aptitude was updating, it kept mentioning ascii instead. But my
/etc/apt/sources.lst is as follows:

hendrik@midwinter:~$ cat /etc/apt/sources.list
#

# deb cdrom:[devuan_ascii_2.0.0_amd64_netinst]/ ascii main non-free

#deb cdrom:[devuan_ascii_2.0.0_amd64_netinst]/ ascii main non-free

deb http://pkgmaster.devuan.org/merged beowulf main non-free contrib
#deb http://pkgmaster.devuan.org/merged beowulf main non-free contrib
deb-src http://pkgmaster.devuan.org/merged beowulf main non-free contrib

deb http://pkgmaster.devuan.org/merged beowulf-security main non-free contrib
deb-src http://pkgmaster.devuan.org/merged beowulf-security main non-free contrib

deb http://pkgmaster.devuan.org/merged beowulf-updates main non-free contrib
deb-src http://pkgmaster.devuan.org/merged beowulf-updates main non-free contrib

deb http://pkgmaster.devuan.org/merged beowulf-backports main non-free contrib
deb-src http://pkgmaster.devuan.org/merged beowulf-backports main non-free contrib
hendrik@midwinter:~$


The only mentions of ascii have been commented out.


-- hendrik