I have a secondary battery in the CD/DVD bay on a Dell D631. With battery installed Ubuntu 14.04 64bit won't boot, stalls at "trying to unpack rootfs image as initramfs". Without secondary battery, it boots fine. I can add battery once booted and it detects it and shows charging / power levels.But once turned off will not boot again till battery is removed and CD / DVD drive replaced.
It used to boot fine on Ubuntu 13.10 32bit