Yesterday I got the new boards in the mail - and they look good!
I actually got the castellations right this time:
Notably, it soldered much better than last time, as expected XD I'm pleased with how the bare PCBs turned out.
This project has been difficult to build. The BGA-packaged OSD3358s aren't cooperative, and they are difficult to obtain. The boards take a long time to fabricate. This is why my project logs are so far apart time-wise. I think the boards I have should work at this point, I don't know of any reason they wouldn't, other than being difficult for me to make at home. I don't have a proper reflow oven or solder stencils (but I'm probably going to get the latter).
If anyone knows of a good, cheap source of OSD3358, or a better way to disassemble pocketbeagles, let me know.
Yesterday I made a failed attempt at recovering an OSD3358 from a PocketBeagle. Whatever solder they use melts at the same temperature, or very near temperature to, the OSD3358's solder ball melting point, probably higher than 225C. The PocketBeagle fell, throwing the OSD3358 inside my oven... and ruining all of the solder balls on the bottom of the package.
I find that it's all too easy to ruin the package like this, this is the third one I've messed up, and they aren't cheap. The chip was already messed up, so I removed all the solder debris from the bottom and soldered it to my board anyway. It's not working yet, we'll see if I can make it work despite it's bad fate over the next several days. In any case, here's what it looks like on a board:
I should be ordering more of the OSD3358s. The reason I tried desoldering from the pocketbeagle is because, for some reason, the pocketbeagles are cheaper than the OSD3358 in USA. Perhaps it is different in China. If anyone knows of a good, cheap source of OSD3358, or a better way to disassemble pocketbeagles, let me know.