Error when saving to flash

Having similar issues, I've been setting NRF Services and trying to save the code getting disconnects. I've manged to do a reset ( insert battery, hold button, wait for self test to finish ) then ran your code above and tried a save() ... disconnected. I think only the last part of the log is the interesting part "BT> SEND ERROR: NotSupportedError: GATT operation failed for unknown reason."

BT> Sending "s"
BT> Sent
BT> RX:"s"
BT> Sending "a"
BT> Sent
BT> RX:"a"
BT> Sending "c"
BT> Sent
BT> RX:"c"
BT> Sending "v"
BT> Sent
BT> Sending "e"
BT> RX:"v"
BT> Sent
BT> RX:"e"
BT> Sending "\b"
BT> Sent
BT> RX:"\b \b"
BT> Sending "\b"
BT> Sent
BT> RX:"\b \b"
BT> Sending "\b"
BT> Sent
BT> RX:"\b \b"
BT> Sending "v"
BT> Sent
BT> RX:"v"
BT> Sending "e"
BT> Sent
BT> RX:"e"
BT> Sending "("
BT> Sent
BT> RX:"("
BT> Sending ")"
BT> Sent
BT> RX:")"
BT> Sending "\r"
BT> SEND ERROR: NotSupportedError: GATT operation failed for unknown reason.
Disconnect callback...
WARNING: [notify_warn] Disconnected
>>> Disconnected