This was the basis for IEEE-1275 Open Firmware, which nobody uses any more but was the standard for SPARC, PowerPC, and post-PowerPC POWER. It’s where device trees came from and frankly is how everything should be booting these days, not u-boot or UEFI or custom secure boot chains (which are entirely possible with Open Firmware too).

There are BSD, GPL, and other Open Source variants of Open Firmware you can get and fool around with today and if you’re building a new product you should still consider whether an Open Firmware would work for you versus one of its inferior successors.