Dell XPS 15-9550 doesn't boot 14.04 (Live USB)

Question

I cannot boot up the default 14.04.3 image flashed into my usb drive, booting up output as here:

Can anyone explained to me how to boot up using the 4.3 kernel? (seemingly possible as implied here:

15.10 Dell XPS 15 (9550) External Monitor not waking

and something called "Hardware enablement" feature of Ubuntu:

https://wiki.ubuntu.com/TrustyTahr/ReleaseNotes

Added Notes (3 March 2016): Just install Ubuntu 16.04 from thumbdrive to an external SSD and it worked! But as usual (same as Ubuntu 14.04) the kernel cannot recognize the internal Windows NVM PCI-e hard-disk. But that is not an issue for me.

Answer 1

To boot the Ubuntu 14.04.3 installation USB media successfully,
highlight Try Ubuntu without installing and press the E key.

Add nouveau.modeset=0 to the end of the linux line.
Then press the F10 key to boot to the Live desktop.

Ubuntu 14.04.3 comes with kernel 3.19, Ubuntu 15.10 with kernel 4.2.
Choose which one you want and download the ISO image accordingly.

LTS Hardware Enablement Stack - the main information from the release notes :
The 14.04.3 point release will ship with an updated kernel and X stack by default.
This newer stack will be comprised of the kernel and X stack from Ubuntu 15.04.

Explanation :

Ubuntu 14.04.1 -> kernel 3.13 (from Ubuntu 14.04)
Ubuntu 14.04.2 -> kernel 3.16 (from Ubuntu 14.10)
Ubuntu 14.04.3 -> kernel 3.19 (from Ubuntu 15.04)

This means that you can update an existing installation to the newer hardware stack.
When you make a clean install of Ubuntu 14.04.3, the latest stack is already included.
But when you want to use the latest kernel 4.2, you will have to install Ubuntu 15.10.