Boot from USB 3.0 external card

[PantelicGR]

Greetings.
I have a motherboard ASUS P5K (LGA775 Socket) and an installed external USB 3.0 card adapter: Via VL800 USB 3.0 Hub 4 Port Card Adapter to PCI-e x1:
https://www.via-labs.com/product_show.php?id=51

Booting from the USB 2.0 interface which this motheboard has is fine. But even though the external USB 3.0 card works fine on Windows 7 with related drivers installed, my external hard drives and SSDs are not shown in the BIOS when they are connected via the USB 3.0 external card.

1) Do you know how to boot from the USB 3.0 external card and how to make my external drives to be shown in the BIOS?
2) Also, could I boot from USB 2.0 with GRUB or a GNU/Linux distribution (Debian 13) installed on it as an intermediary step and then select a USB 3.0 disk which would be connected to USB 3.0 external card to boot from? And if yes, how?

Thanks in advance.

[the_r3dacted]

It really depends on your board and the BIOS. If USB devices can't interface with the BIOS when connected to that card, then there's no hope of booting from it. It might be possible to use Plop Boot Manager to boot from the USB 3 controller, but I don't give it much hope.

[Duke]

Your USB devices must have UEFI boot enabled. Burn your ISO image to stick using Rufus: https://rufus.ie/en/
In the Parition Scheme options select what matches with your machine.

If you can't do that then enable booting from non-EFI devices in the BIOS. This is usually in the Compatibility Support Module (CSM) of the BIOS.
Sometimes this option is hidden until you disable Secure Boot. In some cases you may also need to disable Fast Boot. Then enable the CSM module and set it to boot EFI + Legacy boot devices.
Other possible names: Legacy boot, EFI-but-not-secure devices. Also check the HDD settings of the BIOS.
Still no luck ? Disable LAN Port.

[PantelicGR]

It might be possible to use Plop Boot Manager to boot from the USB 3 controller, but I don't give it much hope.

If Plop Boot Manager may be able to boot from USB 3.0 external card, maybe GRUB or a GNU/Linux distro with USB 2.0 could do it as an intermediary step too?
Because the USB 3.0 card adapter states on its website above that it supports various Linux kernels and legacy Windows.

@Duke
My motherboard is ASUS P5K (LGA775 Socket) and it's old: it doesn't have UEFI, it has BIOS / MBR.
It has no Secure Boot and Compatibility Support Module (CSM).
I have tried to alter BIOS configuration options but still no luck: for example I have disabled Quick Boot, increased the delay to recognize USB devices from 20 seconds to 40 seconds and played around with HDD BIOS settings but the disks on USB 3.0 card are not recognized in the BIOS, only USB 2.0 works in BIOS.
I have also updated the Windows drivers of the USB 3.0 card to the latest version but it didn't solve the problem.

[Duke]

My motherboard is ASUS P5K (LGA775 Socket) and it's old

Old, indeed. Because according to these pages:
https://theretroweb.com/motherboards/s/asus-p5k-rev-1-02g
https://getgui.com/store/en/products/motherboards/asus-p5k-se-epu-lga775-intel-motherboard-c85ba0e-02089-60-mbb6q5-a02-1766610051

and this PDF:
https://icecat.biz/rest/product-pdf?productId=1586109&lang=en

This motherboard has no USB 3 ports. At all.

[PantelicGR]

This motherboard has no USB 3 ports. At all.

Yeah, that's why I got and installed an external USB 3.0 PCI-e x1 card to it.

[Duke]

But your BIOS doesn't care because it has no support for USB 3. I'm not even sure this motherboard can boot from PCI-e.
And the Windows drivers have no effect on the BIOS.

Maybe some hints:
https://github.com/CloverHackyColor/CloverBootloader
https://github.com/CloverHackyColor/CloverBootloader/discussions/352
https://www.techpowerup.com/forums/threads/making-an-old-machine-boot-from-a-pcie-nvme-card.300140/
https://www.youtube.com/watch?v=FnE9SeLZLRc