Booting from express card device

[paradigm-X]

I have a laptop with an express card slot, and I would like to boot a USB drive attached to it with an adapter inserted into it. The adapter is a two-port USB 3 device built-in to the express card, and the hard drive is an SSD inside of a USB 3 enclosure. It might help to show a diagram:

(external) SSD --> USB3 enclosure --> USB3 cable -->2-port USB3 adapter --> express card slot --> laptop (internal)

As it is, the BIOS of this machine allows me to pick among several devices from which to boot, including these: internal HD, eSATA, USB, network, CD/DVD. This machine has a number of USB ports, and whenever I have a USB drive attached directly to one of them, I can boot from it by selecting USB from the BIOS boot menu. Though I cannot select between different USB drives when more than one is attached at same time.

It is not until after I have completely booted that I can even see or access the above drive indirectly attached through the express card slot. I would like to figure out a way to access the USB drive attached with it while yet in the process of booting if at all possible. What do I need to do to figure out exactly which kernel settings pertain to the drivers needed to make this thing accessible during boot? I believe that the 2-port adapter device is identified with 'lspci -k' as this one:

USB Controller: Renesas Technology Corp. uPD720202 USB 3.0 Host Controller (rev 02)
Kernel driver in use: xhci_hcd

I do not see this driver listed as a module when I do 'lsmod'; so I suppose it must be built-in to the kernel. Also, when I do 'lspci -tv', I see it connecting to the following device, which I can see again from 'lspci -k':

PCI bridge: Intel Corporation 5 Series/3400 Series Chipset PCI Express Root Port 5 (rev 05)
Kernel driver in use: pcieport

I might add another point incidentally; it would not in the least bother me if I had to access this manually during boot by typing in something at command line.

[szatox]

when you boot, bios performs some basic tests on hardware, initializes it and provides basic interface to some pieces. I suppose your bios and your express card adapter don't go along, so you must have some extra piece of software (kernel) loaded and running that would take care of it. This means you can't use your expresscard adapter during boot (and perhaps you can't use ANY express card device at all during boot)
it's just a guess on what happens there, but i'm fairly confident it's correct.

[paradigm-X]

> " This means you can't use your expresscard adapter during boot (and perhaps you can't use ANY express card device at all during boot)."

Hi, szatox. Seems like I ought to be able to chain load to that blasted thing at least? I don't know of course, else I wouldn't be asking about it, but can I put enough of Grub, for example, stage 1, into the memory such that even the driver for this device can be recognized, and then "throw it the ball", so to speak, with Grub stage 2? Like I said, I am not sure, but I wonder whether such a thing would be feasible?