Comment 5 for bug 1586838

I tried to install the latest kernel as following:

$ sudo dpkg -i *.deb
(Reading database ... 130671 files and directories currently installed.)
Preparing to unpack linux-headers-4.7.0-040700rc1_4.7.0-040700rc1.201605291331_all.deb ...
Unpacking linux-headers-4.7.0-040700rc1 (4.7.0-040700rc1.201605291331) over (4.7.0-040700rc1.201605291331) ...
Preparing to unpack linux-headers-4.7.0-040700rc1-generic_4.7.0-040700rc1.201605291331_amd64.deb ...
Unpacking linux-headers-4.7.0-040700rc1-generic (4.7.0-040700rc1.201605291331) over (4.7.0-040700rc1.201605291331) ...
Preparing to unpack linux-image-4.7.0-040700rc1-generic_4.7.0-040700rc1.201605291331_amd64.deb ...
Done.
Unpacking linux-image-4.7.0-040700rc1-generic (4.7.0-040700rc1.201605291331) over (4.7.0-040700rc1.201605291331) ...
Examining /etc/kernel/postrm.d .
run-parts: executing /etc/kernel/postrm.d/initramfs-tools 4.7.0-040700rc1-generic /boot/vmlinuz-4.7.0-040700rc1-generic
run-parts: executing /etc/kernel/postrm.d/zz-update-grub 4.7.0-040700rc1-generic /boot/vmlinuz-4.7.0-040700rc1-generic
Setting up linux-headers-4.7.0-040700rc1 (4.7.0-040700rc1.201605291331) ...
Setting up linux-headers-4.7.0-040700rc1-generic (4.7.0-040700rc1.201605291331) ...
Setting up linux-image-4.7.0-040700rc1-generic (4.7.0-040700rc1.201605291331) ...
Running depmod.
update-initramfs: deferring update (hook will be called later)
Not updating initrd symbolic links since we are being updated/reinstalled
(4.7.0-040700rc1.201605291331 was configured last, according to dpkg)
Not updating image symbolic links since we are being updated/reinstalled
(4.7.0-040700rc1.201605291331 was configured last, according to dpkg)
Examining /etc/kernel/postinst.d.
run-parts: executing /etc/kernel/postinst.d/apt-auto-removal 4.7.0-040700rc1-generic /boot/vmlinuz-4.7.0-040700rc1-generic
run-parts: executing /etc/kernel/postinst.d/initramfs-tools 4.7.0-040700rc1-generic /boot/vmlinuz-4.7.0-040700rc1-generic
update-initramfs: Generating /boot/initrd.img-4.7.0-040700rc1-generic
run-parts: executing /etc/kernel/postinst.d/unattended-upgrades 4.7.0-040700rc1-generic /boot/vmlinuz-4.7.0-040700rc1-generic
run-parts: executing /etc/kernel/postinst.d/update-notifier 4.7.0-040700rc1-generic /boot/vmlinuz-4.7.0-040700rc1-generic
run-parts: executing /etc/kernel/postinst.d/zz-update-grub 4.7.0-040700rc1-generic /boot/vmlinuz-4.7.0-040700rc1-generic
Generating grub configuration file ...
Found linux image: /boot/vmlinuz-4.7.0-040700rc1-generic
Found initrd image: /boot/initrd.img-4.7.0-040700rc1-generic
Found linux image: /boot/vmlinuz-4.4.11-040411-generic
Found initrd image: /boot/initrd.img-4.4.11-040411-generic
Found linux image: /boot/vmlinuz-4.4.0-21-generic
Found initrd image: /boot/initrd.img-4.4.0-21-generic
done

But my server couldn't boot up and it shows:

BusyBox v1.22.1 (Ubuntu 1:1.22.0-15ubuntu1) built-in shell (ash)
Enter 'help' for a list of built-in commands.

(initramfs)

I have to roll back to the 4.4.11 kernel. Please advice the next step.