Bug#918322: initramfs-tools: kernel fails to boot with "Gave up waiting for root file system device"

[Axel Ludszuweit]

I have read bug 

        #917607: udev240 makes system unbootable; rootfs not found

Because my working and failing initrd files contain different udev versions, 
the failing one udev240, it may be possible, that this is the cause of failed 
boot.
Bug #917607 description sounds very similar to behaviour of this bug.