News: 0001632266

  ARM Give a man a fire and he's warm for a day, but set fire to him and he's warm for the rest of his life (Terry Pratchett, Jingo)

Flattened Image Tree 1.0 Specification For Embedded Linux Systems

([Standards] 94 Minutes Ago Flat Image Tree 1.0)


The Flattened Image Tree "FIT" 1.0 specification was recently finalized for this container format used by U-Boot on embedded systems for providing various boot components like DTBs, the Linux kernel image, and more into a single file.

The Flat(tened) Image Tree usage can lead to a simpler Linux boot experience for embedded platforms and making it easier to manage deploying of updates with the single container file for providing all of the needed boot assets plus allowing for verified boot functionality and related features. U-Boot spearheaded FIT years ago and since 2024 [1]the mainline Linux kernel has easily allowed buildint ARM64 Flat Image Trees .

While the Flat(tened) Image Tree has been around for nearly twenty years in the U-Boot space, only recently was there the v1.0 tag of the specification. As of yesterday is the [2]v1.0 tag as the " first official release of the FIT specification. "

Meanwhile [3]this commit last week bumped the specification to version 1.0 and tagged its date as 11 April. With this FIT v1.0 specification new additions include security architecture and hash contents documentation, DM-VERITY support for verifying file-system images, shared image data via the image-data property, multi-step loading support, and the configuration command line property. These features were added for FIT v0.9, which hadn't been tagged on GitHub until yesterday. The Flattened Image Tree v0.8 releases and prior were while it lived within the U-Boot space.

The commit bumping the FIT specification to v1.0 notes that there are still some " more major changes in the works " to this important specification for embedded Linux systems.



[1] https://www.phoronix.com/news/Linux-610-ARM64-Flat-Image-Tree

[2] https://github.com/open-source-firmware/flat-image-tree/releases/tag/v1.0

[3] https://github.com/open-source-firmware/flat-image-tree/commit/c210313ebfe360ca7d5855e7fb5684decf340438


Norbert Weiner was the subject of many dotty professor stories. Weiner was,
in fact, very absent minded. The following story is told about him: when they
moved from Cambridge to Newton his wife, knowing that he would be absolutely
useless on the move, packed him off to MIT while she directed the move. Since
she was certain that he would forget that they had moved and where they had
moved to, she wrote down the new address on a piece of paper, and gave it to
him. Naturally, in the course of the day, an insight occurred to him. He
reached in his pocket, found a piece of paper on which he furiously scribbled
some notes, thought it over, decided there was a fallacy in his idea, and
threw the piece of paper away. At the end of the day he went home (to the old
address in Cambridge, of course). When he got there he realized that they had
moved, that he had no idea where they had moved to, and that the piece of
paper with the address was long gone. Fortunately inspiration struck. There
was a young girl on the street and he conceived the idea of asking her where
he had moved to, saying, "Excuse me, perhaps you know me. I'm Norbert Weiner
and we've just moved. Would you know where we've moved to?" To which the
young girl replied, "Yes, Daddy, Mommy thought you would forget."
The capper to the story is that I asked his daughter (the girl in the
story) about the truth of the story, many years later. She said that it
wasn't quite true -- that he never forgot who his children were! The rest of
it, however, was pretty close to what actually happened...
-- Richard Harter