Jacob Olness

@royk Done, I was trying to figure out if there was a way to mark the thread as solved or closed, putting it in the title seems obvious now that you say that. 
The part that was throwing me off is that it was still booting from the SD card. My understanding was that with the NVMe bootloader flashed it will not, under any circumstances, boot from the SD card although this could be outdated or just incorrect. 

The boot directory is on the nvme, so likely the btrfs file system is not supported by the bootloader.
Please put in your title that you've solved it

You might also be interested in tkaiser (who is sbc-bench author) thoughts:

https://github.com/ThomasKaiser/Knowledge

Not sure if there is smth specific re rk35xx frequencies, temps and energy, but definitely there is some interesting stuff re ARM overall and rk3399 in particular, which might be helpful.

I guess some insights might come from the relevant CPU opp-table evolution in mainline and rockchip mailing list on lore.kernel.org There might be some discussion.

Also you might want to create an overlay and test how it works. Just note that some existing frequency overlays do not work since use single opp-microvolt value , eg opp-microvolt = 1000000, which is target microvolt value for given frequency. But at least in some opp-tables triplets approach is used eg. opp-microvolt = 1000000 1000000 1000000 ; which are target, min and max.

Per bindings, both approaches seem legit, but they cannot be used simultaneously.