Re: Accessing local disk from grub2.efi started via PXE

[Pascal Hambourg]

Hello,

Le 01/10/2021 à 03:47, Marek Marczykowski-Górecki a écrit :
> I have a rather unusual setup: I'm loading grub2 (EFI) either from EFI
> over the network, or from iPXE on a USB stick (also in EFI mode). Then,
> I want to load OS from several placed (depending on config). Loading the
> kernel via tftp or http works just fine. But accessing local disk, or an
> USB stick not everywhere (depending on firmware?). "ls" command returns
> just "(proc)" (and a machine with coreboot - also "(cbfsdisk)").

What do you mean exactly by "not everywhere" ?

> I have this issue with variety of disks:
>   - NVME
>   - USB3 mass storage
>   - USB2 mass storage (but USB3 controller)
>
> When grub2.efi is loaded from a local disk, it works.
>
> Things I've tried:
> - loading various modules (ahci, ehci, uhci, usbms etc)

ahci is only for SATA controllers in AHCI mode.
ehci is only for USB 2.0 controllers.
uhci is only for USB 1.0 controllers.

> - looking for "xhci" or "nvme" modules, but I don't see anything like
>    this

AFAIK GRUB does not have xHCI or NVMe native drivers (yet). So it relies 
on firmware drivers for these devices. However the firmware may not 
expose all drives ; I have seen some firmwares which expose a USB drive 
only when booting from it.