# Known-working SD-card reference identification

Captured: 2026-07-14
Source: Notion page `708 Screen Photos`
Source URL: https://app.notion.com/p/39c10e2686d8815b93beea69100f139f
User disposition: newer SD card that works with the old firmware/code

## Preserved image

- Evidence file:
  `work/evidence/notion-sd-card/working-reference-sandisk-industrial-8gb.heic`
- Original Notion attachment:
  `work/evidence/notion-sd-card/notion-708-03.heic`
- Size: 2,068,724 bytes
- SHA-256:
  `3A40313616D5314066950AEA82F7CC46A9B9239EF59EF0C03CE105E18100E2AB`

The descriptive evidence file is byte-for-byte identical to the preserved
Notion attachment.

## Identification from visible label

| Attribute | Identification | Confidence |
| --- | --- | --- |
| Brand | SanDisk | high |
| Product family | Industrial | high |
| Capacity | 8 GB | high |
| Form factor | microSD | high |
| Capacity standard | microSDHC | high; visible microSDHC mark |
| Bus marking | UHS-I | high; Roman numeral I visible |
| UHS speed class | U1 | high; U1 mark visible |
| SD speed class | Class 10 | high; circled 10 visible |
| Exact SanDisk MPN/SKU | not visible | unknown |
| CID, serial, manufacturing lot/date | not captured | unknown |
| Filesystem/allocation-unit format | not captured by the photo | unknown |

## Qualification role

Treat this card as the **known-working reference/control card** for comparative
testing. It demonstrates that the older production datalogger can operate
reliably with at least this SanDisk Industrial 8 GB card according to the
reported field/bench history. It is not, by itself, proof that every card from
the same family, capacity, or label is equivalent.

The paired known failure-prone control is documented in
`work/evidence/sd-card-failure-reference-identification-20260714.md`.

The accelerated evaluation should run this reference card alongside the older
failure-prone card and every candidate sample. Record the CID/serial where the
controller or a fixture can read it, packaging and supplier traceability,
filesystem and allocation-unit size, firmware hash, record count, A/B mirror
integrity, FileX status, free-space change, worst write/flush latency, restart
results, and final host filesystem check for each physical sample.

## Evidence limitation

The front label does not expose an exact ordering number. Do not reduce the
production specification to only “SanDisk Industrial 8 GB”; obtain the reverse
side/packaging markings and electronic CID before using this evidence for a
purchase specification or equivalence decision.
