I would like to post my experience about these ArcNumbers.
I was trying to set this numbers using "setenv arcNumber 2884" on my OpenRD-ultimate without saving the environment ("saveenv") because I wanted to test it first. But the "arcNumber" is only considered by the kernel if you do the "saveenv".
So here is how to make it work with recent kernels:
Marvell>> setenv mainlineLinux yes
Marvell>> setenv arcNumber 2884
Marvell>> saveenv
With these commands we can boot a recent mainline kernel such as 2.6.36. Older kernels don't have support for the OpenRD-ultimate, or need patches (they are in Debian squeeze 2.6.32)
The problem with these environment variables is they break the original Fedora8 / 2.6.22 system. So we have to revert these changes if we want to boot the original environment:
Marvell>> setenv mainlineLinux no
Marvell>> setenv arcNumber
Marvell>> saveenv
So one good solution is to first recompile a recent (>= 2.6.36) linux kernel from the original Fedora8, install it, and then change the arcNumber variable.