BigBoss has recently made it known that problems with Winterboard and SBSettings on firmware 3.1.2 are due to the installation of Icy through Blackra1n. GeoHot fact, he would have included a very old version of this application, and when it is installed through Blackra1n, overwrites the new "dpkg" which causes severe damage to the entire system. Therefore, the advice is to only install Cydia and then maybe, then, to proceed with the installation of Icy using the same Cydia.

Keep this in mind ..