Having problems booting your build-root.
I've build and installed the image, boot loads it
OK, decompress, runs, gets just past the:
VFS: Mounted root (cramfs filesystem) readonly
and then I get a:
Kernel panic: No init found. Try passing init= option to kernel
Looking at the image.param section seems OK:
command=root=/dev/mtdblock init=/linuxrc video=acorn:dram:384k