HOWEVER, the GRUB_GFXPAYLOAD_LINUX setting I used was "text" (yes, literally "text"). The wxh was actually supposed to be the graphics resolution "640x480" (see post #17) but for me, that left it in graphical mode and failed to allow me to enter my password. Using "text" forced it into text mode, which works (but is not pretty). At least now I can login on the first boot.
Was experiencing the same bug (https:/ /bugs.launchpad .net/ubuntu/ +source/ cryptsetup/ +bug/1375435) and this workaround worked for me.
HOWEVER, the GRUB_GFXPAYLOAD _LINUX setting I used was "text" (yes, literally "text"). The wxh was actually supposed to be the graphics resolution "640x480" (see post #17) but for me, that left it in graphical mode and failed to allow me to enter my password. Using "text" forced it into text mode, which works (but is not pretty). At least now I can login on the first boot.