Hi Daniel, I think I might be suffering this bug too. I've just installed plymouth (from testing repos -i run pure testing- : 0.8.8-6+deb8u1) which loads using uvesafb with explicit resolution. I was thinking it might be some wrong configuration issue until I found this report. I'm pretty much in that situation of splash working until it finishes booting and something preventing the system from dropping into gdm3. With text theme or by pressing ESC before the end of the boot process it'll load gdm3 normally and the system'd be fully stable.
I'm using nVidia card with propietary driver, installed via DKMS. I don't know how to provide more information. Might someone send me a private e-mail explaining how to add the plymouth debug option to kernel? Cheers
