Encrypted Persistent USB only boots on USB2.0 - NOT USB3.0

Hello, I have done an LVM Encrypted install to a 64GB USB3.0 Flash Disk which, when I insert into the USB2.0 slot, boots and works perfectly every time.
However, I would like to run this on the USB3.0 port (for obvious speed reasons) but it does not boot from there.

An ordinary live install boots perfectly on the USB3.0 slot, just not the installed version.
If this was a problem with the USB3.0 port, wouldn't it be a problem for every boot?

I know I can just do a persistent live USB but Kali doesn't really give you any option to be able to do that with encryption as well :(

Computer is an Alienware M14XR2


Any ideas guys?

Ok I seem to have fixed the problem.

I re-installed kali the usual way, automatically letting it work its magic with the encrypted LVM as before but because I had a better feel of the installer this time (having installed Kali several times now on a few different systems) I felt comfortable having a bit of an explore.
The problem existed in the location of the boot loader. Kali wants to automatically put the boot loader on the MBR of the first HDD. Last time, I got a bit confused, knowing that I didn't want the boot loader there I selected <BACK> as I thought selecting <NO> would create a problem and I would have to wait another 3 hours to install the system all over again. Selecting <BACK> does take you back to a selectable menu where you can go back to various stages of the install. At this point I selected LILO as a boot loader option as the GRUB option just kept taking me back to the same place. LILO installed and away we went. That's where it was left and it wouldn't boot on the USB3.0 slot.

THE FIX:
Instead of selecting <BACK> or <YES>, you can select <NO>. It doesn't abort the install and it doesn't 'not' install a boot loader. It then asks you where you want the loader to go. I just typed /dev/sdc in the line where it asked and now I am enjoying USB3.0 goodness.


(Sorry for the long winded post but I like to be descriptive)

Thank you for the descriptive post and solutions. I am sure other will find this informative as well. Good work.

Well, it seems as though I'm not out of the woods yet. It only booted the very first time after the install.

So after multiple resets and a little raging, I decided to put the live USB back in and see if I could reload the boot loader. It doesn't let you do that though.
So I ran the step - DETECT DISKS and the USB3.0 stick started flashing. I thought I'd give it another go so I reset and boom! head shot

So now I gotta figure out why my system doesn't detect the USB3.0 unless it's prompted to and can anyone think of anything I can try rather than manually detecting it each time? (There are no options in bios to do so - Running V. 10 bios which is what the system came with (Alienware M14XR2))