The Boot Chain of a RISC-V Board: From Silicon to Ubuntu 26.04(github.com)

When you press the power button on the SpacemiT K3 Pico-ITX, Ubuntu 26.04 appears on the serial console about 30 seconds later. Between those two events, five distinct software layers run in sequence, each one handing off to the next. Understanding what each layer does - and why it exists - matters the moment something goes wrong, or the moment you want to put a different OS on the board.