@wizard
Thank you, I've already downloaded Rockchip Developer Files and found Rockchip GDK, sources for some games, FWTools, but I can't find firmware sources anywhere
In this thread I founded some links, so now I have sources for RK27SDK_NEW and RK2608_4G_DEMO (probably old version, as I see in sources it have no support for FLAC format). But sources for firmware RK2606 I can't find anywhere.