Like many of you, I love RB—primarily for its gapless playback ability (and its much faster database scanning). I'm running the latest build on an 8GB V2, along with a 64GB Sandisk expansion card.
After I loaded another bunch of ~30 MP3s, my Fuze would freeze with only the yellow RB banner showing. Removing the expansion card allowed it to boot as it should. Hmmm, I thought. When connected directly to my PC, the exp. card showed 23.2 GB free. I thought that maybe I was at the upper end of file allocation for this card (formatted as FAT32), so offloaded a number of directories to see if freeing up some space on the exp. card would help. It didn't.
I then offloaded a number of unused RB folders (e.g., Games and such) and a few larger MP3s from the Fuze's internal memory, giving it about 1/2 GB free in which the OS can do its thing. That helped, and at least now my Fuze will boot RB with the exp. card inserted.
Note that, right after boot, wheel operations frequently do not function. They seem to become active only after a minute or two. Also, the display still frequently scrolls diagonally from UL to LR, so trying to make a menu selection with a wonky display is challenging.
Hopefully this report will make sense to those of you doing dvlpt on subsequent builds. I had read about known memory leaks and such, so perhaps my report will help you sort such thins out going forward. Thanks!