We can get working snapshots.debian repositories for all stages using method I found in DigabiOS live-build configs:
- set mirrors to
snapshot.debian.org for required date
- create special apt configs for all stages
STAGES="bootstrap chroot binary"
for stage in ${STAGES}
do
mkdir -p config/includes.${stage}/etc/apt/apt.conf.d
cat << EOF >config/includes.${stage}/etc/apt/apt.conf.d/99-snapshots
Acquire::Check-Valid-Until "false";
EOF
done
But this method didn't work after latest jessie patches (I think after python migration work revert) because contents of config/includes/bootstrap ignored during build process.