>>> Is 2GB only working reliably on a 2b5 or does it also work on a 2b3 board?

>> https://morph.zone/modules/newbb_plus/viewtopic.php?topic_id=12611&forum=11&start=31

> it randomly crashes here. So no luck for me. Will have to look for a 2b5 board

...or you try to get your hands on the very same RAM modules that were reported (see link) to work with the 2B1 board revision.