Memfault Retroactive Chunk/Symbol File Ingest

RE: Memfault Retroactive Chunk/Symbol File Ingest

NoahPendleton — Wed, 18 Mar 2026 17:16:46 GMT

Note also that unlike heartbeat data, coredumps will be automatically reprocessed if a matching symbol file is uploaded later. Syed Maysum's suggestion about using the Memfault CLI to facilitate symbol file upload is excellent- before flashing a build you want to send Memfault data from, you can run a command like this:

❯ memfault --org-token $MEMFAULT_ORG_TOKEN --org $MEMFAULT_ORG --project $MEMFAULT_PROJECT upload-mcu-symbols build/zephyr/zephyr.elf

See the link provided for more reference information, including how to generate the MEMFAULT_ORG_TOKEN.

Thanks!
Noah

RE: Memfault Retroactive Chunk/Symbol File Ingest

Syed Maysum Abbas Zaidi — Wed, 18 Mar 2026 12:52:55 GMT

Hi,

Yes Heartbeat/metric data that arrived before a matching symbol file was uploaded cannot be recovered. However, as soon as you upload the symbol file, all future heartbeat reports from that device will be decoded correctly going forward.

For your development workflow, since every firmware flash creates a new Build ID, the recommended approach is to script the symbol file upload as part of your build process using the Memfault CLI. This ensures the symbol file is always uploaded automatically right after each build, before the device starts sending data.

You can find instructions here: https://docs.memfault.com/docs/mcu/symbol-file-build-ids#uploading-symbol-file-with-build-id

Best Regards,
Syed Maysum

RE: Memfault Retroactive Chunk/Symbol File Ingest

musclemadness — Tue, 17 Mar 2026 19:04:51 GMT

The Q&A assistant suggests from documentation that is avoidable by not letting devices upload before adding the symbol file. This is really a development workflow question, wherein the actual symbol file is totally valid between builds (No changes to chunk format) but the unique ID varies.