• You can use normal microSD cards of type SDHC with your BitBox02
• MicroSD cards of type SDXC are not supported
• There is no minimum size requirement, the backup file is very small
• We recommend going for microSD cards from a quality brand such as Sandisk or Transcend
• Higher speed SD cards can sometimes cause issues, your best bet is an SD card with a speed class of 10 or lower

Formatting

• If not done by default, you should be format it using MS-DOS (FAT) or vFAT for its format.
• After you have formatted the microSD card, never plug it into your computer again, only into a BitBox02.