Block-Level NOR Backups on OpenWrt

A configuration backup cannot recover every firmware failure. On NOR-flash devices, a block-level backup can help analysis or recovery, but writing the wrong MTD partition can brick the router.

Identify first

Run cat /proc/mtd and save the output. Match partition names to documentation for the exact model and never guess /dev/mtdX. Confirm storage capacity and an external destination.

Make a copy

Use the release-appropriate reader, for example dd if=/dev/mtdX of=/tmp/partition.bin, only after verifying X. Hash it with sha256sum, copy it to another machine with SCP, and keep an offline copy. Do not put a dump containing sensitive data in a public repository.

Verify and restore

Record model, layout, version, and compare size/hash across copies. For restoration prefer the official recovery, TFTP/web recovery, or UART process. Never flash a whole dump when the documentation calls for one partition only.

Source

OpenWrt Generic NOR backup .