I was actually able to get it to work tonight from EM Mode. 188.8.131.52 is working nicely (so far).
Excellent, good work
When you say "got it to work from EM mode"... I'd guess you built U-Boot and the new kernel in your 2.6.x system, and rebooted to the 2.4.x EM mode for the 'test RAM build' and 'write to flash' stages?
I'd guess also that in the "test RAM build" stage you managed to get the new U-Boot to boot your existing 2.6.19 kernel from the hard disk?
Those guesses are mostly right. I haven't written to flash yet--I am still on my first boot into 184.108.40.206, and haven't yet rebooted. I'm going to look around to find a later patched version of u-boot, and experiment a bit with the defines, before I write to flash. (I really want to delay as long as possible having to deal w/ this u-boot stuff again.) Among other things, I think the fail order should be hdboot then emmode, not flboot. I don't think flboot will work when you have a 2.6.20 partition on your drive, so the fallback, I think, should be EM.
Also, I did not get the new u-boot to boot my existing kernel (which is 2.6.18 slyver) from disk. I had been told in this thread that that wouldn't work because there's no dts file, so I didn't try it.
Actually, on my penultimate attempt I had several failures getting the ram build to load (these were my own fault--typo in the patch to the u-boot ram binary) and when I finally did get it loaded it had lots of chksum errors and wouldn't go into em mode. My next attempt did not have any chksum errors and worked going into 220.127.116.11 right off the bat, but I didn't try emmode. So, I have to make sure it goes into EM before I flash also.
One other thing for the next person who tries it: On the first load, 2.6.20 did not recognize my USB external drives. They worked find after I manually started hotplug, though. I think (guess) the issue is that the slyver kernels had the USB storage modules built in, and that 2.6.20 has them dynamically loading. But that's just a guess.
And another thing: I didn't do anything to change tty's or avr's. The only change I made was to fstab. So, maybe there's some aspect of 18.104.22.168 that isn't really working--but I haven't seen it yet. Can anyone suggest why its working for me without doing those things?