{
  "status": "shipping",
  "advantages": [],
  "limitations": [],
  "supersedes": [],
  "supersededBy": [],
  "firstSeen": null,
  "lastSeen": null,
  "updated": "2026-11-06",
  "slug": "emmc-life-time-estimation",
  "term": "eMMC Device Life Time Estimation",
  "aliases": [
    "DEVICE_LIFE_TIME_EST_TYP_A",
    "DEVICE_LIFE_TIME_EST_TYP_B",
    "eMMC lifetime estimate"
  ],
  "definition": "eMMC Device Life Time Estimation reports estimated average wear of memory types A and B relative to their estimated maximum lifetimes.",
  "note": "The A/B fields occupy EXT_CSD bytes 268/269. Codes 0x01 through 0x0A identify successive ten-percentage-point bands of used life; 0x0B means the estimated maximum has been exceeded. Zero is undefined and 0x0C-0xFF are reserved. [emmc-health-standard]\n\nThe pinned mmc-utils decoder gates this generic reporting at eMMC 5.0. Preserve both raw values and the device-specific meaning of A/B rather than inventing a universal NAND-cell-type mapping. [mmc-health]\n\nMore detailed, device-specific wear reporting can supplement the coarse endurance estimates. A band is not an exact wear percentage, remaining calendar lifetime or calibrated failure probability. An unchanged code between observations does not demonstrate zero additional wear within that band. [kingston-lifecycle]",
  "related": [
    "emmc",
    "emmc-pre-eol-information",
    "wear-leveling"
  ],
  "citations": [
    {
      "id": "emmc-health-standard",
      "title": "JEDEC JESD84-B51 (February 2015), sections 7.4.22-7.4.24, pages 182-183; TI-hosted copy",
      "url": "https://e2e.ti.com/cfs-file/__key/communityserver-discussions-components-files/791/JESD84_2D00_B51-_2800_1_2900_.pdf",
      "accessed": "2026-11-06"
    },
    {
      "id": "mmc-health",
      "title": "mmc-utils c6692d5: health-command revision gate and lifetime/PRE_EOL decoders",
      "url": "https://kernel.googlesource.com/pub/scm/utils/mmc/mmc-utils/+/c6692d5f9bf1ab6fbf5694a0b61477621cc4d016%5E!/",
      "accessed": "2026-11-06"
    },
    {
      "id": "kingston-lifecycle",
      "title": "Kingston: eMMC Life-Cycle Estimating, Validating & Monitoring (January 2023)",
      "url": "https://www.kingston.com/en/blog/embedded-and-industrial/emmc-lifecycle",
      "accessed": "2026-11-06"
    },
    {
      "id": "analysis",
      "title": "Hesela: eMMC, UFS and RPMB: interface, boot and security boundaries",
      "url": "https://hesela.com/analyses/emmc-ufs-rpmb-boundaries/",
      "accessed": "2026-11-06"
    }
  ],
  "provenance": [
    "Source-reviewed field semantics, not measurements from a device or a JEDEC conformance test.",
    "The limits on calendar-time, failure-probability and unchanged-code interpretation are editorial inferences from the field semantics."
  ]
}