Hi reey and fedup,
thank you for your insights, which helped me booting Arch Linux on the CB5-311 with U-Boot!
Reey, your post from January 6th was very helpful, with the "spi-deactivate-delay = <500>" and "setenv stdin cros-ec-keyb".
Fedup, when I followed your instructions from January 9th I initially only got a "device not found" on U-Boot - but I learned somewhere that you can run "run" on some of the "presets" seen in the output of "printenv", and that got me going in the right direction. I tried "run scan_dev_for_boot", but it was missing "distro_bootpart". So I provided that :
$this->bbcode_second_pass_code('', 'setenv distro_bootpart 2')
Just to be on the safe side I also did:
$this->bbcode_second_pass_code('', 'setenv devnum 1')
That's all:
$this->bbcode_second_pass_code('', '
run scan_dev_for_boot
')
...well, almost. After the next reboot I did a "saveenv" after the two "setenv", and now U-Boot boots my config from /boot/extlinux/extlinux.conf automatically.
I'm not interested in overclocking, more in the frequency scaling, and possible power savings (and colder legs, when using the chromebook on top of my lap). I'd also like to try different kernels more easily, which U-Boot seems to be very good for. It's already reading symlinks on my boot device, so installing several different kernels at once, and linking to the latest only, like Debian is doing by default, should be doable. I noticed archlinuxarm only has one version of linux-armv7, so I can't install say version 4.18 and 5.0 at the same time? I think I'm going to give Debian another try on an SD card, to see how it handles this on ARM (and to compare how well other things are working).
It looks like U-Boot is even supporting an interactive menu for kernel selection, pretty much like GRUB... quite interesting.