I'll throw my name down on the list, too. Exact same problems as organik in FW 2.0.1.
Any new packages that I install from Cydia
after restoring from iTunes backup cause my iPhone 3G to lock completely. I have dozens of App Store apps that are restored from iTunes. As described by others, the packages themselves seem to install without issue, and the "Return to Cydia" button pops up. However, after a few seconds back in Cydia, the small progress wheel appears in the top status bar, making the device unavailable, just as others described. The progress wheel spins for a few minutes, and then it freezes, too. The large progress wheel then appears in the center of the screen, barely visible as it is displayed on top of the frozen screen. It spins for a couple of minutes, during which time the iPhone chirps twice if connected to the USB cable. Finally, some of the pixels blaze bright white and the device freezes completely. A hard reset is required, but the iPhone is unable to get past the boot screen. It has to be dropped back into recovery mode and re-imaged from scratch.
This happens no matter what packages I install from the Cydia app (at least those that would try to create an App icon: BossPrefs, NES, Quake, WinterBoard, IntelliScreen, MobileTerminal, iPhone/Java, etc). However, I don't experience this problem if I install Cydia packages before restoring from the iTunes backup (including my dozens of App Store apps), and similarly if I front-load the IPSW with many Cydia packages through the pwnagetool. Also, if I
update an already-installed package, it seems to work without issue.
NOTE: My root partition size is 800MB.
Also let me say: despite this pretty severe issue, Cydia is an awesome package manager!
