since you periodically wipe your device, you should at least get another secondary device to store your password file on (PC, tablet, or something else).
Since I will always test out new builds. I guess it's time to buy a new device.
The old fashioned way of paper and pen still remains the best method of saving passwords to the best of my perspicacity, anyway.
Nothing can beat the old fashioned ways. Yes sir, I will write it down in a dairy or notebook and store it securely where it will be safe.