Yocto Linux on Atom Z3735G Baytrail - Initialising i915 gives blank screen

I'm trying to build a custom distro for a tablet, using the Yocto Project with the meta-intel layer. Everything builds OK and after flashing to the device, it boots but the screen goes blank when the i915 driver is initialised. Sometimes there are a couple of coloured lines across the screen, which looks to me like the device has crashed completely, though I can't be sure as there is only a USB port on it so I can't get a serial TTY to check it. If I add i915.nomodeset=1 to the command line, the system boots up fully, but doesn't initialise DRM, which I need. The kernel version I'm using is 3.19.5. I've managed to grab a picture of the logging output just before the screen goes off: Does anyone know why this might be happening, and how to fix it? **Update** I managed to get a dump from dmesg with the screen off. You can see it here: dmesg dump