On Fri, Jan 9, 2026 at 2:17 PM Philippe De Muyter wrote:

Hello dfu-utils developers,

I have just discovered dfu files and specifically DfuSe files, and I have read the "DfuSe File Format Specification" in UM0391 from ST.

In UM0391, each buffer is "represented in Big Endian order". I have undersood that as saying that the 32bits value are stored in big-endian order.

Interesting, the document also says "The Suffix buffer is represented in Little Endian order".

Typically most things in USB standards uses Little Endian, to my knowledge.

Now I see that dfu-utils expects and stores 32bits values in little-endian order. Is there another document that specifies that ?

As you have seen, src/dfuse.c assumes little-endian (through its quad2int() function). I haven't seen any bug reports on this. Does ST provide any sample DfuSe files? In my experience all files that work with ST's own tools also work with dfu-util, but this is maybe based on little data.

Best regards, Tormod