Is it possible to build ubuntu for R3 from scratch?
If so, are there recommended instructions to be followed, such as build environment and commands? It is preferred to customize .dts and files to build image for NAND/eMMC.
Thanks, Bruce
My images repo builds ubuntu images using debootstrap (minimal packages),but not completely from source
Building for nand is much more tricky as it cannot contain a filesystem like ext4. I have a nand branch there which builds an ubinized image with kernel and buildroot initrd. Afaik enough as rescue system.
There are many ways to get linux on the R3. My archlinux arm repo is one of them and also there is an option for Ubuntu, although what I do there probably is not what you want. Maybe you can be more specific what you want.