Dell Optiplex 3070 - support for 2 EFI partitions?

Hi

I don't quite understand the question....

A single main board with a Boot Manager that can point to several different partitions (with assorted OS's installed).

Then various boot loader's can takeover and boot multiple OS's.

Many years ago I had opensuse as a SecureBoot install and an "MBR Legacy".

Currently I have (Linux Mint CLI output)....

efibootmgr 
BootCurrent: 0002   
BootOrder: 0002,0004,0000,0001

Boot0000* Windows Boot Manager HD(1,GPT,808302de-97fb-4e77-af37-9993f5a0dfed,0x800,0x82000)/File(\EFI\Microsoft\Boot\bootmgfw.efi)

Boot0001* rEFInd Boot Manager VenHw(99e275e7-75a0-4b37-a2e6-c5385e6c00cb)

Boot0002* Ubuntu HD(1,GPT,808302de-97fb-4e77-af37-9993f5a0dfed,0x800,0x82000)/File(\EFI\ubuntu\shimx64.efi)

Boot0004* Debian HD(1,GPT,808302de-97fb-4e77-af37-9993f5a0dfed,0x800,0x82000)/File(\EFI\Debian\shimx64.efi)

Can you please explain/state what you hope to achieve.

@anne_droid​ 

I have researched the topic online.

My plan is 2 drives, one operating system on each.

As I understand, there are pros and cons of having 2 EFI partitions, one for each of the operating systems that my computer has.

The main 2 things that attract me:

1- Apparently, Windows might modify some things causing Linux to not be able to boot.  Maybe a Windows update does this.  If Windows has its own EFI partition, that risk is reduced.

2- I want to be able to take the drive with Linux installed out of the computer and put it in another computer.  for that, I need an EFI partition on "drive 2."  Also, I want the "original" computer to still be able to boot Windows.  For that, I need an EFI partition on "drive 1."

Hi

""If Windows has its own EFI partition, that risk is reduced.""  Not really IMHO.

Well do that.

Occasionally Windows updates have taken priority, but it is easily repaired.

Drive 1 should retain the Windows Boot Loader;

Drive 2 will have Linux installed and the GrUB Boot Loader, which will have the options for Linux and Windows to choose from.

Removal of Drive 2 will place  Drive 1 in prime position.

Drive 2 may not automatically boot if placed in an alternate machine.

################

Below is a bit of a stretch, but perhaps worth researching.

OP plan is 2 physical drives, one operating system on each.

each drive should have its independent single EFI partition in a UEFI system, if the OS on that drive was clean installed in the absence of another bootable drive containing an OS already.

a clean install here means single device present that has all its partitions deleted in custom mode.

Logically it is simpler to install Linux on drive 1 when drive 2 is not connected. Then install Windows in drive 2 when drive 1 is not connected.  When two independent clean OS install are completed and successful boot on its own separately confirmed in the absence of the other drive, connect both drive to pc simultaneously.

Press F12 after power on and manually select one UEFI device as primary boot drive, Windows boot manager will be updated to contain a link to that device EF partition.  In best scenario pc will always boot from that drive onwards automatically.

If you remove that drive, you should press F12 again to select the other UEFI drive as new boot device, and WBM will be updated too to prepare a smooth boot next time.  If you don’t press F12 to select new boot device, PC may give error of no bootable drive.

@anne_droid​ 

"Occasionally Windows updates have taken priority, but it is easily repaired."
--I think that what you are saying is that sometimes a Windows update makes GRUB boot manager unable to load when you start the computer.  When that does happen, is there kind of a standard procedure for dealing with the problem?  Or is it more "reinvent the wheel" each time?  I think I am still a little uncomfortable with dual booting Windows because my Linux OS is about 10x as important as Windows.  But, I can manage with being locked out for a couple of days.

"Drive 1 should retain the Windows Boot Loader;"
--The Windows Boot Loader is on the EFI system partition, correct?

"Drive 2 will have Linux installed and the GrUB Boot Loader, which will have the options for Linux and Windows to choose from."
--Ok.  So there is an EFI partition on drive 2, which Linux installer has created.  On that drive, I am guessing, is a bootloader manager, and that bootloader manager has recognized the Windows EFI partition and "incorporated" it into the options.

"Drive 2 may not automatically boot if placed in an alternate machine."
--Is this a general comment about drives with Linux installed or your statement is mainly applicable to Drive 2 in your example?

"Below is a bit of a stretch, but perhaps worth researching."
--And that is to avoid all of the nonsense with needing thumb drives, and all of the negatives associated with those--a waste of money, easy to misplace, annoyance to dispose of?   

@redxps630​ 

"Logically it is simpler to install Linux on drive 1 when drive 2 is not connected. Then install Windows in drive 2 when drive 1 is not connected.  When two independent clean OS are completed, connect both drive to pc simultaneously."
--Interesting.  I have never heard of that approach before.  The advice that is "hashed and rehashed" is to install Windows first.  But, you might not be disagreeing with that, just more advocating for the disconnected drive approach.

"Press F12 after power on and manually select one UEFI device as primary boot drive, Windows boot manager will be updated to contain a link to that device EF partition.  In best scenario pc will always boot from that drive onwards automatically."
--F12 brings up a UEFI boot manager.  For people with dual boot Windows and Linux, I believe that will show choices "Ubuntu" (or "Debian," etc), Windows Boot Manager, and a phrase that refers to the USB drive.  But, with the process you are describing, it will look different?  Or, did you mean press F2 at startup, which brings you into a full blown UEFI tree, with a lot of configuration choices, including "boot priority" list?

Here is the motivation for my OP

"Not all firmware versions will support booting from more than one EFI partition. Many just search the disk(s) for the first EFI partition that they can find."

source (first answer, 3rd paragraph)
https://superuser.com/questions/1664442/windows-linux-uefi-dual-boot-does-efi-partition-need-resizing

But, it's good that we are covering a lot more ground than just that.  This has definitely opened my eyes to some things.

I was thinking of having two devices each running independent Windows OS.  OP is correct that if one device has Linux the other Windows, then F12 brings up UEFI: Linux and Windows boot manager if BIOS has a record of booting from these devices before.

If BIOS has never seen a boot device before (CMOS is cleared or a device is completely new), F12 will present a list of UEFI bootable devices by their names, such as UEFI: Samsung SSD without inside knowledge of what type of OS is in the device.  But if BIOS has seen a boot device before and successfully boot from it before, then a memory of boot manager is written in BIOS.  In that case F12 will bring up Linux and Windows Boot manager.

It does not matter which OS is installed first in a single device clean OS install scenario.  Either way is fine, install Linux first or Windows first.   One" start from a clean slate " approach is that after both devices OS clean install are done and tested running separately, user can go into UEFI bios to wipe all memories of previous UEFI boot device,

this can be done via "Delete Boot Option" in BIOS to remove Windows boot manager etc.

connect both devices to PC and press F12 at power on to choose a boot device.  this chosen device will become the default boot device on future boot.

If you chose Linux device, pc will always boot from this device and ignore the other device containing Windows OS.  

If you chose Windows device, a new Windows boot manager will be established in bios and pc will boot from that device and ignore Linux device.

It is when BIOS having multiple "boot managers" in record when things become hairy.

@redxps630​ 

So it was the Windows boot manager that showed 2 Windows choices?  In other words, not the UEFI boot manager?

Hi

I have had a windows update make the windows boot manager the priority, so just re-arrange the BIOS boot manager order and put GrUB first.  A matter of a few seconds.

#####################

"Drive 1 should retain the Windows Boot Loader;"
--The Windows Boot Loader is on the EFI system partition, correct?

YES.

#############################

OK, EFI partition sizes....   100/150 is quite common for MS.  250- 600 is a broad range for the broad range of LINUX distro's et al.

600 mb gives scope for a recovery OS to be installed there for emergency use. 

EG: OneFileLinux is a single-file, EFI-based Linux recovery environment designed for data recovery, system repair, and diagnostics.  Based on Alpine Linux and the Linux kernel 6.12, it operates without installation by booting directly from the EFI System Partition (ESP).

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

"Drive 2 may not automatically boot if placed in an alternate machine."
--Is this a general comment about drives with Linux installed or your statement is mainly applicable to Drive 2 in your example?

The alternate machine is not likely to have the Boot Manager entry initially, and of course things like Drivers, Secure Boot and firmware may not match. 

It applies to MS Windows more than most linuxes in my very poor opinion.

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Because I dont know what OS's you have installed and what you contemplate installing further,

I wish you luck;

with the signoff that the best boot loader, by far, is rEFInd by Rod Smith, allegedly.

If you start from clean (no UEFI boot option in bios), clean install Windows OS on two drives separately and boot from each drive successfully, then connect both drives to pc, Windows boot manager will show two Windows to boot from.

If you have 2 drives in PC each with same Win10/11 OS, time is of the essence.  Eventually, Windows will corrupt one or both drives and give BSOD.  The only way to defeat BSOD then is to reload OS.  It starts with something like "Disk Checking."

You do have enough time to go into Disk Management and reformat (even if the formatting is the same) to wipe one of the drives and use for storage.

Windows will still detect if there's another boot drive in the PC with the same OS.  This is from experience.  I went through quite a bit of troubleshooting to figure it out.

May be have Win11 on one drive and Win10 on the other.