I've seen this happen to several people (including myself now) but I haven't seen a resolution. When you get to the end of the installer in SPRecovery you get thrown back to the beginning of the install. Then once you answer keep or wipe data it throws you back to the beginning again. Infinitely. I've gone through the update several times now and this just happened out of no where. So it seems to be a bug. Does anyone know how to get out of the infinite loop?