[quote user="Kai Scheffer"]Is it possible to use parts of the embedded Flash to save data, e.g. log dat?[/quote]
Yes.
[quote user="Kai Scheffer"]If so, what are the limits, eg complete bank, pages, blocks to release and how many erase/write cycles are guaranteed (error protection)?[/quote]
As per datasheet. Though generally if you are about to use the BLE stack, such module
is already implemented in there and ready for use by the user.