Barebox is an attempt to work around the limitations that U-Boot shows through its age. Originally dubbed U-Boot v2, it now has a different name because its design goals are different.
Barebox now support support arm, powerpc, mips, nios2, blackfin, x86
One of the great thinks with barebox, it's the sandbox.
Basically you can develop and debug generic feature
1) compile it
for other arch than x86 or ppc you need to use the next branch or the mainline
As I just recently fix the support for all host
ARCH=sandbox make sandbox_defconfig
now just start it
# ./barebox barebox 2011.10.0-00119-gad62fdb-dirty (Oct 15 2011 - 11:38:46) Board: sandbox Malloc space: 0x7f679f24b010 -> 0x7f679fa4b010 (size 8 MB) Open /dev/env0 No such file or directory no valid environment found on /dev/env0. Using default environment running /env/bin/init... barebox:/