That is why there is so much confusion over efi because sometimes it will work if put in the same directory as the linux efi bootloader

I don't use UEFI myself so am just basing on what I have read. The link below gives a pretty detailed explanation of UEFI on Ubuntu/Mint. The original bootinfo output posted by the OP showed windows installed to the MBR on one drive and Grub on the second which would mean he is not using UEFI. Now he has installed Mint in EFI mode which generally creates problems

https://help.ubuntu.com/community/UEFI

The link below explains a method to supposedly use both?

https://help.ubuntu.com/community/In.../UEFI-and-BIOS

Where the grub.cfg resides in efi mode is distro specific. Some distros have the file in /boot/grub and other distros require the grub.cfg file to reside on the efi partition with the efi boot files. I may be wrong but I think mint installed in efi mode puts a config file on the efi partition pointing to the /boot/grub/grub.cfg file, so in a situation like this that file may not exist with the boot files on the efi partition.

Good job!
I don't know of any solution for that situation. The problem is that when you chose to boot Mint, your computer boots in UEFI mode. That means when you see the Grub menu (IF you do...) the computer has already booted in UEFI mode - meaning that it is not going to boot the non-UEFI Windows. At least, that is the process as far as I understand it.
What I would do, if it were my computer, is delete all the partitions and the GPT partition table on sdb, and change it to msdos partitioning, and re-install Mint in non-UEFI mode. That would eliminate any incompatibilities between Windows on sda and Mint on sdb.
To delete the GPT partition table is very simple. Boot the live Mint DVD or USB, open the gparted program. Click on sdb > Device > New Partition Table > msdos
Then use gparted to create the partitions you want for Mint. Close gparted and run the Mint installer. Chose the Something Else option, and install to the partitions you created, making sure to install the bootloader to sdb, not sda.

Unfortunately, sdb isn't suitable for old-style partitions because it's a 3TB drive.

It seems strange that this would stop grub2 finding Windows, however - whatever mode it booted up in, those drives are still all visible, including the Windows system partition which contains its bootloader etc. Does it somehow need some extra information from the UEFI BIOS?

Not really. If you are booting Mint in EFI then it looks on the FAT32 partition for its EFI files and if you select windows it will look on the EFI partition for the windows EFI files which you do not have since windows is not installed in EFI mode. The files below are the Ubuntu/Mint EFI files and are on the FAT32 partition. If you had windows installed EFI, the windows files would also be there obviously with different names.

The second link in post 17 above explains a method of using EFI/MBR but it seems to have a lot of restrictions and doesn't seem like it would work well on an everyday computer since some updates will break it.

That statement is correct if you are using the conventional 512 bytes per sector. If you use 4 KB sectors (4096-byte logical sectors), msdos partitioning can address up to 16 TB on an "Advanced Format" drive (which a new 3TB drive should be).
I have seen that in various places, you would have to research the exact procedure for setting it up.
Here is an example, quoted from http://ubuntuforums.org/showthread.php?t=1536933
Model: Seagate FA GoFlex Desk (scsi)
Disk /dev/sdc: 3001GB
Sector size (logical/physical): 4096B/4096B
Partition Table: msdos

Number Start End Size Type File system Flags
1 28.7kB 3001GB 3001GB primary

Another example, quoted from http://ubuntuforums.org/showthread.php?t=2246256
Model: WD Ext HDD 1021 (scsi)
Disk /dev/sdb: 3001GB
Sector size (logical/physical): 4096B/4096B
Partition Table: msdos

Number Start End Size Type File system Flags
1 1049kB 3001GB 3001GB primary

Unless you are using only one or two drives of very small capacity, I would exhaust your efforts to resolve your troubles using GPT before you fall back to using the old-school MBR. Consider 7 Ways to Dual Boot ... and Dual Boot Linux Mint 17.

The GUID Partition Table or GPT of itself is not a bad thing. There are many advantages over the previous approach Master Boot Record or MBR. When disks were small, four "primary" partitions was effective. Larger disks caused deployment of the "extended partition" which could then contain "logical partitions." Today's giant drives, by comparison, benefit from an approach that permits an all-but-unlimited number of partitions numbered 1,2,3,... It is unfortunate that the GPT features got tangled in with "secure boot" and other aspects of the unified extensible firmware interface (UEFI).

There are other boot managers besides Grub.

rEFInd says it allows "Auto-detection of EFI and BIOS boot loaders."
http://www.rodsbooks.com/refind/features.html

http://forums.linuxmint.com/viewtopi...164018#p843296

Dear Kylotan and others,

If you are having problems booting up your Linux or other Operating Systems (OS), you can use the very easy, useful, and very handy, program "Boot-Repair-Disk". This program can repair most booting up issues by just booting to this program and selecting the first option "recommended repair" which is usually a one click repair for fixing your booting problems. This program has saved my butt many times when I was experimenting with installing Linux distributions. I have provided a link below where you can download "Boot-Repair-Disk" as an ".iso" file and create a live usb, or CD or DVD from; or if you can boot to your Linux partition, then you can install this directly into your Linux using the instructions below.

Downloading "Boot-Repair-Disk" programs (32 bit or 64 bit versions,if you are unsure, choose 32 bit)
http://sourceforge.net/projects/boot-repair-cd/files/

Information on Boot Repair from Ubuntu forums
https://help.ubuntu.com/community/Boot-Repair

Installing "Boot-Repair-Disk" to your Linux using PPA mode, bring up your "terminal" and type in:
(obviously you have to run it after installing it to repair your booting up problems)

sudo add-apt-repository ppa:yannubuntu/boot-repair
sudo apt-get update
sudo apt-get install -y boot-repair && boot-repair

If you cannot boot up your local drive(s), or want to boot to another device, then there are very good programs available to allow almost any machine to boot to your local drive(s), external USB drive(s), or CD/DVD drives, like "SuperGrub2 Boot Loader" and "PLOP" which you can burn to CD/DVD or another USB drive. With these programs, I have been able to boot to the USB drives that I have created using the default Linux Mint 17 program and "unetbootin". I prefer to use the "Super Grub2 Boot Loader" program disk to boot my USB drives; It shows all installed operating systems on the machine and lets you choose which one to boot - very cool. I'm not sure, but Super Grub2 may also be able to repair or reinstall the boot information or Grub files.

Super Grub2 Disk
http://www.supergrubdisk.org/super-grub2-disk/

PLOP
http://www.plop.at/en/bootmanager/download.html

Hope this helps ....

I'm still looking for a thorough explanation of whatever Windows™ 7 and 8x does during its install along with what it does and needs and uses during its boot.

I understand the Linux® boot pretty well (grin) at least up until init takes over. I used to understand the Master Boot Record (MBR) boot in that context. Now UEFI and GPT have me completely confused.

One wrinkle that I know says that Win-7 must be 64-bit to use GPT and UEFI features, with or without "secure boot."

I think that means:

• power on and enter CMOS/BIOS settings dialogs
• enable UEFI features
• disable "secure boot" (typical for folks running Linux)
• accomplish installs with MBR or GPT partitions as desired

Thanks in advance,
~~~ 0;-Dan

With BIOS firmware, the BIOS looks at the MBR for instructions on booting. With EFI firmware, the EFI mechanism includes much more of the booting information in the EFI itself, and looks only at the ESP (EFI System Partition).

A couple of good pages to start with:
The EFI boot process. - http://homepage.ntlworld.com/jonatha...t-process.html
Linux on UEFI: A Quick Installation Guide - http://www.rodsbooks.com/linux-uefi/

Thanks, Dan.

1 members found this post helpful.

1. I, too, am named Dan. (grin)
2. I, too, live in Austin.
3. Sorry, I'm a Baylor fan.

Drop a private message (PM) if you want to find a beverage...

Cheers,
~~~ 0;-Dan

I sincerely appreciate the invitation, but the Ayn Rand quote in your sig indicates that we would not get along.
I prefer Democracy - it isn't perfect, but it is better than any alternative.
I realize that people who preach anti-social or un-democratic philosophies, like Ayn Rand and Machiavelli, have their followers, but I am not one of them.

Austin Greetings, philosophy not withstanding...

Our political and social "differences" and discussions of them are what might make things intellectually interesting. That said, I understand that it is difficult, in these times, to attempt discussion of many topics because so few folks are able to remain open minded in the presence of opinions they disagree with or that they find distasteful. I'm not suggesting that you might be one of those folks. Rather, you have no idea how I might respond to or react to whatever might come up in conversation.

I respect you openness and honesty,
~~~ 0;-Dan