hesela.deveMMC PRE_EOL information
eMMC PRE_EOL_INFO is an EXT_CSD status field that classifies reserve-block condition as normal, warning or urgent.
EXT_CSD byte 267 encodes undefined as 0x00, normal as 0x01, warning as 0x02 and urgent as 0x03; 0x04-0xFF are reserved. Warning corresponds to 80% reserve-block consumption. [1]
Generic eMMC 5.0 reporting separates this status from lifetime A/B estimates; device-specific diagnostics may provide more detail. A reserve-block status must not be substituted for endurance-used percentage. [2]
Normal is not a guarantee against all failure modes, and an undefined or reserved code is not evidence of a healthy device. Keep the raw status, device identity and observation time when comparing reports.
BKOPS_STATUS is separate: EXT_CSD byte 246, bits 1:0, reports background-operation urgency, with 0x02 indicating performance impact and 0x03 critical work. PRE_EOL 0x03 instead reports urgent reserve-block condition; the matching code does not make the states equivalent. [1]
Relations
Citations
- JEDEC JESD84-B51 (February 2015), sections 7.4.22-7.4.24 and 7.4.33, pages 182-183 and 186; TI-hosted copy
- Toradex: eMMC (Linux), generic and vendor-specific health status
Further reading
Sources & caveats
- Interpretation is scoped to the cited standard and implementation guidance; no device failure was observed or predicted.
- JESD84-B51 table 105 gives no numeric urgent threshold or strict/inclusive comparison; no additional numeric threshold is inferred. [1]
- The limits on healthy-device conclusions are editorial inferences from the status definitions.