Well, I've gotten as far as decompressing the ce_ramdisk. Used "file" to find out it was a .gz file which contained an ext2 filesystem...which contained a smaller, slimmed-down filesystem which contained rootfs.jffs2....I made a small Arch Linux chroot and used mkfs.jffs2 to make my own jffs2, renamed it rootfs.jffs2 and replaced the one in the ce_ramdisk. I grabbed a kernel from sheeva.with-linux.com. I "setenv mainlineLinux no" and "setenv arcNumber 2097". I tftp'ed in the new kernel in the same place, changing the hex size of it of course, and tftp'ed the new, modified ce_ramdisk in the same place. I modified the bootargs's size as well, to reflect the new size of ce_ramdisk. I then booted. I didn't get far. "Ok, booting the kernel." is where it died. The kernel was recognized by u-Boot as 2.6.31.1.

So I went back and flashed the ce_kernel and reset arcNumber and mainlineLinux to blank values. I booted and the familiar Linux output started rolling down the screen, but it had a problem with the ramdisk (I think) when it couldn't "open an initial console (try passing init= to the kernel)". I had initrd= in the bootargs and all.

I realize this procedure of changing the rootfs.jffs2 is dirty, but it's been my first try. It's pretty unbelievable that PlugComputer.com doesn't have any guides to flashing an OS on the internal NAND, only to USB/SD cards.

I'll try setting mainlineLinux to yes tomorrow. How about the jffs2? where should that go? The PlugComputer wiki describes how to do it from within an already running Linux environment, but doing it through u-Boot would be great.