Simple fix to avoid ucf prompts when grub *hasn't* changed its template is to run 'DEBIAN_FRONTEND=noninteractive dpkg-reconfigure grub-pc' in the image build scripts after /etc/default/grub has been populated. This will confirm the script populated answers to the debconf questions as the known-good values, and avoid the next grub upload showing up as having a changed template.
Simple fix to avoid ucf prompts when grub *hasn't* changed its template is to run 'DEBIAN_ FRONTEND= noninteractive dpkg-reconfigure grub-pc' in the image build scripts after /etc/default/grub has been populated. This will confirm the script populated answers to the debconf questions as the known-good values, and avoid the next grub upload showing up as having a changed template.