grub2 doesn't know of eSATA on some computers?

[Zhang Weiwu]

Problem: grub2 can't find device on eSATA. Detail:

On my desktop, grub2 in its commandline mode (Ctrl+c on boot menu) can 
tab-complete eSTATA harddisk detail, by double-tapping TAB after this:

grub> root (hd1

I thought it a universal feature. So this is what I do on my laptop:

1) It has Windows VISTA OEM on it. Take out the hard disk with a skewdriver, 
enclose it in eSATA case, connect it to the laptop.

2) Install a new hard disk on the laptop, install Linux on it (OpenSUSE 
13.1), leaving the eSTAT case connected to it. The Linux installer knows 
there is a Windows and offers to multi-boot it.

3) During booting, grub2 offers to boot into OpenSUSE or "Windows Vista on 
/dev/sdb1". The former works fine. The later, once chosen, gives an error 
that it cannot find the device 58F80A0DF809F9D8, which is the UUID of the 
OEM Windows VISTA partition.

The intention is of course to boot Windows Vista from eSATA. Since I only 
use Windows occassionally, I prefer to put it on portable eSATA and leave 
the whole harddisk (SSD) to Linux. (I googled, most people ask about how to 
boot Linux from eSATA: isn't Linux more useful and deserve a main position?)

Now that I have grub not able to find the device for Windows VISTA, I enter 
commandline mode (Ctrl+c on boot menu), double-tap TAB after this:

grub> root (hd1

Result: nothing. In fact, if I do tab-completion at
grub> root (hd

without typing '1', it autocompletes to hd0, meaning grub2 consider only one 
hdd in existance.

My question:

Is it by design some laptops won't let grub2 boot from eSATA - a dead-end, 
or merely a configuration issue? The laptop is Toshiba Portégé R600 with 
very limited BIOS options (no config option about eSATA at all and harddisk 
does not show up in BOIS once installed or connected).

I expected someone answer that Windows cannot be booted from external 
harddisk, even if I manage to get past grub2. It is not true.  I saw someone 
booted it from eSATA, unsure if his Windows is specially prepared though. 
However I never saw anyone to boot Windows from an USB hard-disk.

Best regards.