1.5.6: After Cydia's mishap with aptickets from 6.0 --> 6.1.2 (causing soft-dfu loops), iFaith now includes an apticket validation. You can utilize the check by browsing for blobs when building a signed IPSW or by downloading existing blobs from Cydia's/iFaith's SHSH server under iFaith's "Show available SHSH blobs on server" button.
1.5.6: Now dumps iOS 5.2.1/6.1.3 blobs on 3GS/A4 devices.
1.5.6: Fixed a bug when downloading iFaith blobs.