dm-crypt notes

Error message

WARNING: keyslots area (998400 bytes) is very small, available LUKS2 keyslot count is very limited.

Check your partion - remove partition and increase the size.

Error message

Cannot wipe header on device /dev/disk/by-partlabel/cryptsystem.

The device may be readonly. Execute as root

blockdev --getro <device>

Return 1 if read-only - 0 when read-write