To fix the white screen problem you have to download the asset zip from the buildbot site and extract it into your media folder on your sd card.
Also make sure you download the RPX zip not the ELF zip..
Thanks I figured out the assets shortly after posting, by reading the 1st post heh.
I stayed away from RPX version because I found HBLauncher 1.4 had a low success rate on my WiiU, so I stuck with earlier version that does not support RPX. But now I have Hatchii installed I guess I can upgrade to HBLauncher 1.4... I forgot! I'll try it and try RPX...