Changing current partition table from legacy to UEFI for a dual boot.

[jinx748]

I have Ubuntu 14.04 installed on a 2 TB drive and windows installed on a 1 TB drive. I have been trying for days to get them to dual boot. After much reading, scouring the web and reinstalling windows trying to fix my problem I think my problem is that the Windows drive is not UEFI while the Linux drive does have a UEFI partition table. So While I can manually go into the Bios and change the boot order, each drive will boot fine on its own but when trying to dual boot from the grub menu while the UEFI drive is first in the bios the windows drive will not boot at all. Now I seem to be getting other issues after my last windows installation. But they all seem to be related.

Is it possible to change the partition table to UEFI on the windows drive without having to reinstall windows? Also, if I do have to reinstall windows again and recreate the partition table on the 1TB drive I would make it aGPT partition table correct?

sudo parted -l

Model: ATA ST31000528AS (scsi)
Disk /dev/sda: 1000GB
Sector size (logical/physical): 512B/512B
Partition Table: msdos

Number Start End Size Type File system Flags
1 1049kB 106MB 105MB primary ntfs boot
2 106MB 516GB 516GB primary ntfs
3 516GB 992GB 476GB extended
5 516GB 992GB 476GB logical fat32
4 992GB 1000GB 8634MB primary linux-swap(v1)


Model: ATA WDC WD2002FAEX-0 (scsi)
Disk /dev/sdb: 2000GB
Sector size (logical/physical): 512B/512B
Partition Table: gpt

Number Start End Size File system Name Flags
1 1049kB 538MB 537MB fat32 boot
2 538MB 794MB 256MB ext2
3 794MB 2000GB 2000GB


Error: /dev/mapper/ubuntu--vg-swap_1: unrecognised disk label

Model: Linux device-mapper (linear) (dm)
Disk /dev/mapper/ubuntu--vg-root: 1991GB
Sector size (logical/physical): 512B/512B
Partition Table: loop

Number Start End Size File system Flags
1 0.00B 1991GB 1991GB ext4


Error: /dev/mapper/sdb3_crypt: unrecognised disk label



Sudo fdisk -l

Disk /dev/sda: 1000.2 GB, 1000204886016 bytes
255 heads, 63 sectors/track, 121601 cylinders, total 1953525168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x426ecf55

Device Boot Start End Blocks Id System
/dev/sda1 * 2048 206847 102400 7 HPFS/NTFS/exFAT
/dev/sda2 206848 1007063039 503428096 7 HPFS/NTFS/exFAT
/dev/sda3 1007063040 1936660479 464798720 5 Extended
/dev/sda4 1936660480 1953523711 8431616 82 Linux swap / Solaris
/dev/sda5 1007065088 1936658431 464796672 b W95 FAT32

WARNING: GPT (GUID Partition Table) detected on '/dev/sdb'! The util fdisk doesn't support GPT. Use GNU Parted.


Disk /dev/sdb: 2000.4 GB, 2000398934016 bytes
255 heads, 63 sectors/track, 243201 cylinders, total 3907029168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000

Device Boot Start End Blocks Id System
/dev/sdb1 1 3907029167 1953514583+ ee GPT

Disk /dev/mapper/sdb3_crypt: 1999.6 GB, 1999602974720 bytes
255 heads, 63 sectors/track, 243104 cylinders, total 3905474560 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000

Disk /dev/mapper/sdb3_crypt doesn't contain a valid partition table

Disk /dev/mapper/ubuntu--vg-root: 1991.1 GB, 1991069663232 bytes
255 heads, 63 sectors/track, 242067 cylinders, total 3888807936 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000

Disk /dev/mapper/ubuntu--vg-root doesn't contain a valid partition table

Disk /dev/mapper/ubuntu--vg-swap_1: 8531 MB, 8531214336 bytes
255 heads, 63 sectors/track, 1037 cylinders, total 16662528 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000

Disk /dev/mapper/ubuntu--vg-swap_1 doesn't contain a valid partition table


Here is what is in /ETC/Grub.d/40_Custom


menuentry "Windows 7 (loader)" {
insmod part_msdos
insmod ntfs
set root='(hd1,msdos1)'
chainloader +1
}

[ubfan1]

You could more easily make the Ubuntu into a BIOS boot than the Windows into a UEFI boot I think. Do you even have any Windows UEFI bootloaders? If you can get the bootmgfw.efi (Windows bootloader), you could try to make a 300M FAT partition for EFI by chopping off a piece of one of the existing ones, then put the bootloader into /EFI/Microsoft/Boot/bootmgfw.efi (I think that right, from memory). The grub custom file is for the old style grub, so you'd need the new grub-efi installed. Then your Windows boot paragraph will use the /EFI/Microsoft/Boot/bootmgfw.efi instead of the "-1" in the chainloader.

[fantab]

GPT has advantages (https://wiki.archlinux.org/index.php/GUID_Partition_Table#Advantages_of_GPT).
Install Windows7 in UEFI mode (http://www.sevenforums.com/tutorials/186875-uefi-unified-extensible-firmware-interface-install-windows-7-a.html). To do this you will have to delete all the partition on Windows HDD or /dev/sda ... hope you have a good data backup.