I recently reflashed from amber and was putting it off for a few months before doing so. I anticipated both a lengthy process and numerous issues along the way, but found neither.
I highly recommend using Angus’s update branch for the flash script described in this post. Successful Reflash to Byzantium
That branch takes care of two things.
- Updates the default encryption key for the luke partition.
- Resized the encrypted partition to the whole drive.
After flashing, restore your files, restart and enjoy what almost feels like a new device.