Not being an expert, I confess to being confused as to the method of booting you are showing. You show a bunch of "sf writes", which according to what docs I can find, are for writing FROM memory INTO flash... but I never see you put anything into that memory. In other words, what are you writing into the flash before you boot?
[What this output log looks like is that you wrote uninitialized memory into the flash, then tried to boot from it that data. But maybe I missed something (like reading the boot image from a tftp or sd card)]
In any case, assuming you've got your procedures correct, but seeing how you might typically boot, what you describe sounds like: when you DON'T install your application into the boot kernel, everything works fine. When you DO install it, it might change the kernel size. I'm going to go out on a limb and guess that you forgot to change the size in your "sf" command that copies the boot image? If you use the old size, perhaps you don't copy the whole image, and perhaps it fails a consistency check by the boot loader.
