About gentoo installation in embedded systems.

Gentoo installation under arm, ppc or any other platform in its complexity is comparable to installing debian. That means, it is not complicate.

What do we need?
We need a board with uboot and any kernel, not depended from the current version of FS from gentoo, i.e. the kernel can be of any version. It is very convinient to have a port for connecting a usb stick to have gentoo filesystem on the usb stick.

There are the uboot variables to download the kernel via tftp, and filesystem gentoo from usb stick.

set newBootCmd 'set ethact egiga1;tf $(loadaddr) mrv/brd6282/uImage;bootm $(loadaddr)'
set newBootArgs 'set bootargs console=ttyS0,115200 root=/dev/sda1 rootwait rw loglevel=8 init=/sbin/init'
set new_boot 'run newBootArgs; run newBootCmd;'

Next we go the the website gentoo to the section "downloads", it can be done under thelink http://www.gentoo.org/main/en/where.xml

Download the archive files stage3 for the certain plattform. Stage3 is the root filesystem from gentoo in the minimum enviroment suitable to continue booting into the console and there is an opportunity to continue installation of necessary applications from the command line using the standard utilities of the gentoo.

That's all. Copy gentoo fs to the usb stick.

Added to the end of the file /etc/inittab the line:

T0:2345:respawn:/sbin/agetty -L ttyS0 115200 vt100

Also replace the file etc/shadow with any file with setted password by user root.

Insert the USB flash drive and boot the system - it should be working.

After gentoo get started we can use standard tools to install packages.

Update the Portage tree (a lot of installation scenarios will being downloaded into usr/portage from Internet):

# emerge --sync

initial setup (installing base system):
https://www.gentoo.org/doc/ru/handbook/handbook-x86.xml