> Any idea how the non-held result sets interact with rollback-to-savepoint ?

Try asking in Firebird-Support, since the non-held result set is just
normal Firebird cursor and Jaybird does not introduce anything special here.

Also, I see only one interesting issue here - when you update the
records which were not yet visited by this cursor, then you make a
savepoint, visit some records, issue new update, visit next records and
then rollback to the savepoint and visit the rest of the records. So the
question is Firebird's behavior in different isolation levels.

Roman