Hello,
btw remember that mainline u-boot / kernel *does* actually work... with the Revision 2.2 EOMA68-A20 Cards it just only works for about 90 to 300 seconds and i haven't been able to track down why.
Care to elaborate a bit on that, is there more information somewhere, a bug report, anything ? I ask because the 300 seconds uptime rings a bell, maybe not relevant, but suspicious at least. The kernel was (maybe still is) initializing the timer (if I remember correctly) subsystem 5 minutes before wraparound, just so it is easier to catch bugs, by making those wraparound bugs easier triggerable...
there's clearly a bug somewhere around 4.0rc5 to 4.0rc6 which, if found, fixed, and patched, would make mainline perfectly acceptable for ongoing usage (with the EOMA68-A20).
That should be easy enough to bissect, if you have a reproducer.