Camera card offload guide
How to verify a camera card backup with SHA-256
A checksum is useful evidence about bytes, not a promise about hardware or creative content. The strongest simple workflow records the source hash, re-reads each destination and refuses to hide uncertainty.
Hash a stable source file
Record file size, modification evidence and SHA-256 before copying, then confirm the source did not change while it was read. If the source changes, the file needs review; a stale hash should not be treated as authoritative.
Verify bytes after they reach disk
Compute SHA-256 from a fresh read of each destination file. Comparing only names, counts or copy API success can miss truncated, stale or altered bytes.
Require both destinations to match
For every relative path, compare source, destination A and destination B. The job is verified only when every expected regular file is present at both destinations with matching size and SHA-256.
Resume by proof, not presence
An existing file is reusable only after its size and hash are checked again. If it is corrupt, replace it inside the product-owned job folder and run the same destination re-read used for a new copy.
State what SHA-256 does not prove
Matching hashes do not guarantee drive longevity, correct camera operation, useful image content or a complete long-term backup plan. They prove that the checked byte streams matched at the time of verification.