Sandisk SSD M.2 firmware upgrade


i am upgrading Sandisk SSD M.2 firmware from x300 series to x400 series.

i have below queries:

  1. what are the backup that needs to be taken before SSD Firmware upgrade. I dont want to take back up of the complete disk paritition. i just wanted to take some meta data back up (or) what can be the other back up that can be taken apart from the disk partition , how can i do this?

  2. how to recover from SSD firmware upgrade failure?