Creating the gentoo from scratch was a little tricky, it didn't work the first time because I hadn't changed the profile to not use multilib which is being discontinued.
I have the procedure detailed in a few messages on the Gentoo Forum
I first created the cross tool with crossdev
and then emerge the full system. It missed the /dev files and a few directories which I created by hand, didn't remember the command to do those automatically. I basically copied from an other gentoo images the devices directory names in question.
I then copied the newly created stage3 to /usr/src I change make.conf to not expect to do cross compiling but on a riscv64 system.
I ported fchroot from Funtoo to run on Gentoo, only needed to change the line with Python as Funtoo is handling that differently from Gentoo.
I was then able to chroot on the stage3. It worked like a champ, I could emerge some new files. I plan to copy it on my website some day
https://suzielinux.com/
As for the board I do not have it yet, it is going to be the BeagleV
I signed for it but if I don't get one then I will just buy one when it comes out.
What is missing on it the kernel and u-boot which I will create when I have the information for those.
My stage 3 only supports those languages that interest me which are French, English, Spanish and Chinese. You can add any language that you want and then run the update world to have the system adapt. My default locale is fr_CA which can be changed to whatever is supported.
Michel