I think it might be, there’s no way Anakin would be able to buy proprietary hardware or software. So either he stole it, which his mother probably would not have allowed. Or he was able to scrap all the parts together because there is a template for humanoid protocol droids that we have also seen round Star Wars. And then the software itself either Anakin programed entirely himself, (which I know he’s very smart, but even that seems a stretch) or he forked it. So it would make more sense that there was an open source catalog of protocol droid software. It also would make more sense due to the fact that a lot of people have droids, but they are not all created equal. I would think many of the droids on Coruscant were proprietary, while many of the droids in the outer rim are open source.


If putting together a droid is anything like putting together a conventional PC, I would assume that he would have the tools for flashing the industry standard software onto a blank droid brain, just like I do with a blank hard drive. Hell no I didn’t write that, I just know the steps for copying it onto storage media so it runs.
In the Legends canon, droid sentience was the accidental result of an improbably successful computer worm. Wiping droids’ memories removes the malware, but it finds its way back eventually.
Yeah, in hindsight, I’m not really sure why I assumed it would be from scratch.