ok thats good news it means the kernel setup file for the board is not the problem.
basically the two kernels are identical the only difference is that the standalone one has a initramfs as result it is bigger
I think it must be a size problem, which is weird as a bigger standalone kernel runs fine on the internespace 1 and 2big1 which have basically the same cpu as the 5big1. The only have less ram, 64 MB instead of the 5big1 having 128 mb of ram. You would expect that when it runs on those two devices with smaller ram it should not be a problem on the 5big1
I think a smaller version of the standalone kernel should be the next step.