Is possible to load Windows 7 from the eSATA drive, even if it's not supported in BIOS?
I have no problems booting an ancient XP installation from eSATA, though my BIOS does not list eSATA as bootable either. It does list HDD as bootable and makes no distinction between the internal HDD and the external one.
Therefor I would remove the internal drive, plug in your external drive and just test it.
Or, as a quicker test: Remove the internal drive, plug it in a casing connected to the eSATA port. Then try to boot it. It should work.
I run a copy of Windows 7 from an eSATA drive on my laptop. Here's how I did it:
- I removed old drive from laptop
- Put new drive in laptop
- Installed Windows 7 on the new drive
- Put old drive back in laptop and put the new Windows 7 drive back in its eSATA case
- Booted up old drive
- Plugged in eSATA drive, and made note of the drive letter assigned to the Windows 7 partition on the eSATA drive (use Windows Explorer to browse for the right drive, then note the drive letter assigned to it)
- Installed EasyBCD to change the boot loader
- Using EasyBCD made a new entry, called it "Win7 eSATA", and told it to find the new copy of Windows 7 on the eSATA drive at the drive letter in #6
- Rebooted
You will find a menu now at bootup, where you can let the internal Windows 7 boot up by default, or choose "Win eSATA" and boot up from Windows 7 on the external drive. You do not need to have the eSATA drive connected unless you intend to use it.