This applies to 2.6.31 & 2.6.32 kernels for certain, but probably other newer kernels as well.
I'm a user of mkelfImage; I am currently unable to get an .ebi generated by mkelfImage to boot properly - I can't load it directly, or via a mechanism like kexec.
The moment the command (be it etherboot/gpxe, or kexec) tries to load the kernel, the system immediately reboots.
If I directly kexec a kernel (minus mkelfImage), the kernel loads correctly, so it appears the problem is in mkelfImage.
Unfortunately, I don't know how to fix it, and I _have_ to use mkelfImage to generate .ebi images for my systems.
I've tried 2.6.27, 2.6.31, 2.6.32; of those, 2.6.27 (and older kernels, work fine. 2.6.31 & 32 results in an .ebi that causes the system to reboot.
Thanks, Troy Telford