Hi Marek, In reference to: https://lists.denx.de/pipermail/u-boot/2021-October/465221.html
I have several Kirkwood boards, and currently support these boards in mainline: Sheevaplug, Zyxel NSA310S, GoFlex Home, Dockstar. I also have a few out-of-tree Kirkwood u-boots that have not been submitted for mainline yet. I did not see the stack size problem, or any other problem. And I'm running the 2021.07 version. Regards, Tony