Re: Boot windows on external disk : "not a valid root device"

[Hervé Guillemet]

Le 02/01/2013 01:33, Vladimir 'φ-coder/phcoder' Serbinenko a écrit :
> On 02.01.2013 01:14, Colin Watson wrote:
> 
>> On Wed, Jan 02, 2013 at 12:31:14AM +0100, Hervé Guillemet wrote:
>>> I have a new Asus N56VZ laptop and replaced the Windows hard drive by a
>>> SSD with Linux installed. EFI Grub2 successfully launchs Linux.
>>> Now I'd like to boot Windows from the original hard drive mounted by USB.
>>>
>>> No matter what I try, either using grub.cfg or command line, Grub's
>>> chainloader fails :
>>>
>>>> set root=(usb0,gpt1)
>>>> chainloader ($root)/EFI/Microsoft/Boot/bootmgfw.efi
>>> Error: not a valid root device.
>>>
>>> The content of the drive may be seen using "ls".
>>>
>>> What's the exact meaning of "not a valid root device" ?
>>
>> It indicates that either no UEFI device handle corresponding to that
>> device was found, or that no UEFI protocol interface is available for
>> that device handle.  In other words, "can't work out how to talk to that
>> device using UEFI".
>>
>> I think your device naming is dubious: as far as I can see, GRUB's
>> efidisk module does not fully support calling a disk "usb0".  The "ls"
>> command should show you the list of available disks and partitions, or
>> you can type "set root=(" and then use tab-completion.  If the disk is
>> truly only accessible as "usb0", then perhaps efidisk needs some work to
>> support that.
>>
> 
> Other than loopback, all devices follow the naming scheme insluding type
> prefix as detailed in manual. "usbN" means that the device is accessed
> using GRUB own modules. To use chainloader on EFI you have to avoid
> loading any USB modules and use hdX names.

Ok, I tried, but then the external disk is not visible and ls only shows
me hd0. Can you see a possible solution ?


-- 
Hervé