Hi Simon, Marty,
I'm interested in getting U-Boot to work with Kevin as well, but don't have a Servo (or the willingness to open up the case yet), so I've been trying to boot from depthcharge as in README.chromium-chainload.
I don't have a way to see serial output and I see no other signs of life. Can you give me a tested configuration that immediately powers-off or reboots a Kevin so I can confirm what I'm doing works on the chainloading side? I mean I can boot Linux, but trying the same with U-Boot just gives me a blank screen even after accounting for a lot of things.
Meanwhile, I've wrote some code to automate making depthcharge partition images, and to enable the display on Kevin (and perhaps Bob). Since I don't know if chainloading works, I don't know if these are broken or not either. I'm unsure about sending untested patches to the list, so I put them up here if you want to take a look (and maybe test/fix them?):
https://github.com/alpernebbi/u-boot/tree/rk3399-gru-kevin/wip
They're not really things that'd make a non-booting Kevin boot, though. I hope at least some of it can be useful in some way.