I have existing win7 instalation which I just moved to 3 tb disc via clonezilla (2tb partition). I wish to extend that partition so I can use all 3 tb of disc space. I've read that because it's bootable partition it must be gpt based and it must be launched by efi firmware. As I do have uefi (asrock p67), I've conerted mbr to gpt by using gdisk, then rebooted my PC. But now during boot there is "Select proper boot software or insert media" after POST checks. I am obviously missing some step, but Googling around didn't get me the answer I was looking for

  • I believe to be able to boot in uefi, the OS installation registers itself against the BIOS. Therefore you need to install Windows in UEFI boot mode, not sure if you can convert an existing OS to UEFI. – Marcelo Sep 9 '14 at 12:50
  • @Marcelo I really don't want to reinstall OS and more than 1.8 tb of stuff. Is there any workaround for this? For example OS repair tool like fixmbr in old win xp recovery console? – PiotrK Sep 9 '14 at 13:04
  • @PiotrK - You are indeed correct there is indeed a command you can run. But the error in question indicates there isn't an EFI partition can you confirm it actually does exist and contained the proper files? – Ramhound Sep 9 '14 at 13:08
  • @Ramhound I was able to boot Linux Live cd and I was able to mount all partitions and access ntfs filesystem, all files seems ok and in place. What is the EFI partition? – PiotrK Sep 9 '14 at 13:39
  • 1
    @PiotrK this could be of help: mpspartners.com/2013/10/… – Marcelo Sep 9 '14 at 13:44

Okay, thanks to @Marcelo comment I was able to figure this out, 10 hours later...

1.) First, the ASRock P67 Pro3 has undocument feature (or bug, if you wish to call it so), it is amusingly hard to boot a CD as UEFI. The UEFI option will keep disapearing from boot menu even if you set your SATA mode to AHPI (tested on BIOS 40 version)

2.) Sooo, prepare a UEFI pen-drive (at least 4 gb) with Windows Installer. Instructions here: http://www.eightforums.com/tutorials/15458-uefi-bootable-usb-flash-drive-create-windows.html

3.) Make a backup of system partition. As in my case I was upgreading from old drive, I've already had a backup on it, but in your case do a Clonezilla or similiar backup of everything to another drive of the same or higher capacity

4.) Format drive and set it up as GPT (I used Gparted for this)

5.) Install Windows 7 from pen-drive boot in UEFI mode (F11 after POST checks)

(If it says that it cannot be installed in GPT drive, then you didn't boot it in UEFI mode)

6.) Use Clonezilla again to overwrite windows instalation with your backup

And now here comes the tricky part: if you try to boot your Windows now, you will encounter 0x0000007B BSoD

1.) First of all, boot your Win7 installation pen-drive once more, select repair and wait until it tell you that there were some problems and were repaired (when scanning for system list)

2.) In my case I had to boot pen-drive installer again and select repair again, so the Windows would fix drive file system. Don't know if this is manditory step or just sanity check of NTFS filesystem

3.) Boot pen-drive installer for the third time and select console, then enter: bcdboot C:\windows (replace C: with your windows drive letter, you can see it in the OS picker tool just before you picked console). Then enter

4.) It still won't boot up, until you turn SATA mode back to IDE. I don't know why the hell it works, but it works.

5.) After booting you will be prompted to install disk driver, which will require reboot

6.) FINALLY! You should have Windows 7 working on 2tb+ hard disc :-)

  • You also could have used gdisk in Windows to change the type ID of the 100MB partition from (gdisk)0700 to ef00. Then extended it, reformatted it with FAT32. Then bcdboot would have worked directly. – Milind R Sep 10 '14 at 6:28

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.