UEFI boot and sanhook

[parthy]

I think I've tracked the issue down to the call chain shutdown_boot() -> efi_remove() -> efi_driver_disconnect_all(). The entire subsystem is removed, even though the boot services are still active. Hence, the network connection is gone and the iSCSI disk is no longer available. So the remaining question is if this is intentional or not, i.e., if an iSCSI hook should remain functional after a kernel is loaded (I see the shutdown call in ELF, Multiboot, and Linux loading).

I've tested the shell example on qemu (with drivers e1000 and rtl8139) and on an Intel NUC7 with I219-LM (8086:156f). It seems the problem is not a specific driver, but the fact that a driver is used instead of the UEFI network services.