Comment 0 for bug 1627670

I've just tried both -39 and -40 in xenial-proposed, and both fail to boot on my laptop (dropping to busybox - see the attached screenshot)

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: linux-image-4.4.0-38-generic 4.4.0-38.57
ProcVersionSignature: Ubuntu 4.4.0-38.57-generic 4.4.19
Uname: Linux 4.4.0-38-generic x86_64
NonfreeKernelModules: nvidia_uvm nvidia_drm nvidia_modeset nvidia
ApportVersion: 2.20.1-0ubuntu2.1
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: chr1s 2537 F.... pulseaudio
 /dev/snd/controlC1: chr1s 2537 F.... pulseaudio
CurrentDesktop: Unity
Date: Mon Sep 26 10:42:45 2016
HibernationDevice: RESUME=UUID=934c1be9-b0ee-4b9d-9508-7bfb0af474c9
InstallationDate: Installed on 2016-03-09 (200 days ago)
InstallationMedia: Ubuntu 16.04 LTS "Xenial Xerus" - Alpha amd64 (20160307)
MachineType: Dell Inc. Precision 7510
ProcFB: 0 inteldrmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.4.0-38-generic.efi.signed root=UUID=aa26703d-fe98-42ad-927a-31369b873d93 ro noprompt persistent quiet splash crashkernel=384M-:128M crashkernel=384M-:128M vt.handoff=7
RelatedPackageVersions:
 linux-restricted-modules-4.4.0-38-generic N/A
 linux-backports-modules-4.4.0-38-generic N/A
 linux-firmware 1.157.4
SourcePackage: linux
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 05/27/2016
dmi.bios.vendor: Dell Inc.
dmi.bios.version: 1.05.04
dmi.board.name: 0692Y5
dmi.board.vendor: Dell Inc.
dmi.board.version: A00
dmi.chassis.type: 9
dmi.chassis.vendor: Dell Inc.
dmi.modalias: dmi:bvnDellInc.:bvr1.05.04:bd05/27/2016:svnDellInc.:pnPrecision7510:pvr:rvnDellInc.:rn0692Y5:rvrA00:cvnDellInc.:ct9:cvr:
dmi.product.name: Precision 7510
dmi.sys.vendor: Dell Inc.