@xxxxts: It might be unrelated, but before I overclocked/undervolted with Powerkernel I never had any sudden crashes in MicroB (meaning it closes itself with internal error). It even happens that the device resets itself during browsing. I can strangely enough run pretty demanding games without resets, and that speaks against the clocking.
What I did was trying the different presetschemes and the only one I got working at 250-900 Mhz was the lv scheme. The other caused pretty soon a device reset.
I haven't let's say created a device specific scheme yet by tuning and tweaking and that's maybe what I have to do before saying anything at all. But I would have expected that at least a few of those default schemes would work better than the did.
That's why I went to the conclusion that my device wasn't very "overclockable".

Any clues here?

EDIT: BTW, anything above 900 Mhz on the lv scheme pretty soon resets the device. This is after all a matter of factory yield and depends on the success in the manufacturing process. Some chips are very tolerant whereas some doesn't go much past the "default".