Code:
Setting up grub-pc (2.02+dfsg1-5ubuntu9) ...+ cached_available_ids=
+ case "$1" in
+ . /usr/share/debconf/confmodule
++ '[' '!' '' ']'
++ PERL_DL_NONLAZY=1
++ export PERL_DL_NONLAZY
++ '[' '' ']'
++ exec /usr/share/debconf/frontend /var/lib/dpkg/info/grub-pc.postinst configure 2.02+dfsg1-5ubuntu8
dpkg: error processing package grub-pc (--configure):
installed grub-pc package post-installation script subprocess returned error exit status 20
dpkg: dependency problems prevent configuration of grub2:
grub2 depends on grub-pc (= 2.02+dfsg1-5ubuntu9); however:
Package grub-pc is not configured yet.
dpkg: error processing package grub2 (--configure):
dependency problems - leaving unconfigured
No apport report written because the error message indicates its a followup error from a previous failure.
Errors were encountered while processing:
grub-pc
grub2
E: Sub-process /usr/bin/dpkg returned an error code (1)
Boot is OK but not in a newest Grub2... 
Code:
sudo mv /var/lib/dpkg/info/grub-pc.postinst /var/lib/dpkg/info/grub-pc.postinst.zika
is one of possible solutions...
It worked for me, no promises for others...
