version >= power43 from extras-devel are highly experimental and include USB hostmode patches and u-boot. Do not install them unless you exactly know what you're doing. If it doesn't boot, crashes or shows other issues (no audio etc) please report your configuration (OC, multiboot/Nitdroid/Meego etc installed?).
If you have fcamera and any version >= power40 installed, you also need the updated fcam-drivers.