It is either fails with "No kernel modules ..." or "Mirror does not contain release ..." depending
if access to unstable repository available or not.
According to it's changelog entry 20190702+deb10u3 it is UNRELEASED and this after building debian-installer tried to access unstable repository even mirror/suite and mirror/codename preseed are correct and pointing to stable and buster respectively.
It seems we need to mark it as buster (release) in changelog (e.g. by using dch -m -r from devscripts package) to make debian-installer access.
It is either fails with "No kernel modules ..." or "Mirror does not contain release ..." depending if access to unstable repository available or not.
According to it's changelog entry 20190702+deb10u3 it is UNRELEASED and this after building debian-installer tried to access unstable repository even mirror/suite and mirror/codename preseed are correct and pointing to stable and buster respectively.
It seems we need to mark it as buster (release) in changelog (e.g. by using dch -m -r from devscripts package) to make debian-installer access.