Statusbyte im Flash speichern

Ich habe zwar keine Ahnung vom AVR aber wenn zB die letzte Page im Flash 
noch frei ist dann kannst du dort Daten speichern, allerdings sind die 
Schreibzyklen niedriger ca 10 000 und beim EEPROM 1 000 000 glaub ich.

Habe es eben selber auch gefunden:
16.2. Overview
The Non-Volatile Memory (NVM) Controller manages all access to the 
Non-Volatile Memories. The NVM
Controller controls all NVM timing and access privileges, and holds the 
status of the NVM.
During normal execution the CPU will execute code from the code section 
of the Flash memory (program
memory). When entering sleep and no programming operations are active, 
the Flash memory is disabled
to minimize power consumption.
All NVM are mapped to the data memory. Application software can read the 
NVM from the mapped
locations of data memory using load instruction with indirect 
addressing.
The NVM has only one read port and, therefore, the next instruction and 
the data can not be read
simultaneously. When the application reads data from NVM locations 
mapped to the data space, the data
is read first before the next instruction is fetched. The CPU execution 
is here delayed by one system
clock cycle.
Internal programming operations to NVM have been disabled and the NVM 
therefore appears to the
application software as read-only. Internal write or erase operations of 
the NVM will not be successful.
The method used by the external programmer for writing the Non-Volatile 
Memories is referred to as
external programming. External programming can be done both in-system or 
in mass production. The
external programmer can read and program the NVM via the Tiny 
Programming Interface (TPI).
In the external programming mode all NVM can be read and programmed, 
except the signature and the
calibration sections which are read-only.
NVM can be programmed at 5V, only.