The PicoBoot is an open-source firmware for the Raspberry Pi Pico, allowing it to be used as an IPL replacement chip, running IPL.dol off the root of an SD card connected to one of the usual EXI ports.
Forks
CubeBoot (aka "flippyboot-ipl"), adds the ability to customize the boot animation colours and text. It is compatible with modchips such as PicoBoot.