Just 2GB RAM visible on VIM3_Ubuntu-server-focal_Linux-5.7-rc7_arm64_SD-USB_V0.9-20200530 and lazy fan

I see that the Fan has no problems in Linux 4.9 Kernel,
maybe something is amiss in the mainline kernel

5.4 auto fan was also ok, 5.7 is also auto, but somehow lazier, which results in higher temperatures

Hmm, that is bad, have seen this in any other firmware ?

I think help you with this question