Right. So my base is *not* "ELF is best", but it is "ELF is just fine for this, so why would we need another format, with all infrastructure overhead that requires?". So please start by explaining what is bad, or even just sub-optimal, in using ELF here.
Let's take it one thing at a time.
Ok, that will help :-)
First question.
What is the means by which I can create an ELF file such that the segment data is compressed, but the segment headers are not, and I can know which compression algorithm was used, so that I can do a streaming decompress of a segment into memory, a.k.a zero-copy?
Let me start by firing back another question: why do you want this?
If it turns out you really *do* want this, there is always the PF_MASK_OS field in the p_flags field per segment (an 8-bit field that any OS can use any way it wants -- and coreboot is an OS as far as ELF is concerned).
Segher