Cydia Installer not working (after iOS 6.1 Jailbreak Untethered)

Q: Cydia Installer not working (after iOS 6.1 Jailbreak Untethered).

Saurik (on Reggit):
This will not be as serious of an issue this time around; in addition to how every jailbreak this problem is less problematic, planetbeing said he would finally deploy my "pre-primed Cydia" proposal, so when you open Cydia immediately after the jailbreak it will already have a package catalog from all of the default repositories, and will not need to do a full refresh cycle (which is what really pummels the repositories during new jailbreaks): it will only need to grab the diffs. (That's the one thing I thought random people seeing this conversation may actually want to know; beetling and 0ptimo otherwise correctly covered this suggestion itself.)