KatolaZ <katolaz@???> writes:
> Unfortunately, my enthusiasm left room to frustration. To cut a long
> story short, apt-get dist-upgrade fails on unpacking bash_4.3, and in
> particular it seems that the pre-installation script is bein killed
> with SIGILL (Illegal Instruction).

You could put bash on hold,

echo 'bash hold' | dpkg --set-selections

and see if the remaining installation succeeds. Or download the bash
.deb by hand and try to install it via

dpkg -i

It should also be possible to get coredump from the SIGILL which would
identify the exact program and the faulting instruction/ address. While
I haven't written any ARM assembly[*] for some years, I'm confident to
understand enough of an ARM binary to detemine if this is in fact an
illegal instruction or something else, ie, flaky hardware,