Page processing sequence:
- Repeat with buffer 0 to S-1
- 512-byte data, processing ON
- Repeat with buffer 0 to S-1
- size0 nibbles spare, processing ON
- Repeat with buffer 0 to S-1
- 1 nibble padding spare, processing OFF
- size1 nibbles spare, processing ON
Checksum: Spare area size (nibbles) = S – (size0 + 1 + size1)