Installing some OS's in UEFI and some using Legacy BIOS


  1. Posts : 241
    Windows 10 Pro
       #1

    Installing some OS's in UEFI and some using Legacy BIOS


    Hello,

    I've installed Windows 10 and Ubuntu using UEFI.
    But, now I created a bootable USB for a Linux that does not support UEFI, but only Legacy.
    I mean, when I plug the USB to my laptop, the UEFI does not recognize it, only the Legacy BIOS does.
    Is it possible to simply proceed to install the other Linux using Legacy mode? Or it will cause problems?

    Thanks
      My Computer


  2. Posts : 2,799
    Linux Mint 20.1 Win10Prox64
       #2

    I am never a fan of using dual boot. I have Windows 10 installed on a separate GPT SSD and Linux installed in MBR SSD and run them separately using Boot Menu so they are completely independent from each other.

    I did mention in your other thread that dual booting using MBR is preferable which you can set the Windows boot manager and GRUB boot loader separately. The traditional way is Linux override the MBR and took over the booting process for both Windows & Linux. The non traditional way is to put the GRUB Boot loader in its own partition then use Easy BCD to set up the dual boot, this way they are independent so if there's an update/upgrade from either one, you won't break anything. In addition, you'll get a nice GUI dual boot Menu from Windows, not the ugly GRUB.

    Here's an example:

    1. GRUB controls the booting process for both Windows and Linux
    2. Put GRUB in its own partition and use Easy BCD to set up dual boot.
      NOTE: During Linux installation, you have to tell Linux not to use sda (MBR in Windows) but its own partition.



    Installing some OS's in UEFI and some using Legacy BIOS-linux.png
      My Computer


  3. Posts : 241
    Windows 10 Pro
    Thread Starter
       #3

    Sorry I may have not understood you correctly. I am not too expert in these things.
    The problem now is that I already have Ubuntu and Windows installed on UEFI, but the 3rd OS (another linux) is not shown on UEFI in the bios.

    What exactly is the connection between MBR and UEFI?
    *I will try to do stuff with Easy BCD now.
    **How do I put grub in a separate partition if I haven't done that ? should i reinstall Ubuntu and
    Windows 10?

    ***Earlier I accidentally installed a software called EasyUEFI instead of Easy BCD, is it a bad software?

    ****Should I completely change the bios to ALWAYS run as Legacy instead of UEFI and reinstall all using Legacy?
    (I can't find the connectiom between UEFI/Legacy to MBR/Grub and the bootable OSs . )
    Thank you!

    *Edit: I installed Windows and Ubuntu when my bios was set on UEFI. so in order to make it work, I must remove all, and install them when LEgacy BIos is on and enabled first, right? there is not escape than making a clean install of Windows and Ubuntu from the Legacy menu in the bios instead of uefi?
    Last edited by mibaup; 06 Feb 2016 at 10:47.
      My Computer


  4. Posts : 2,799
    Linux Mint 20.1 Win10Prox64
       #4

    EasyBCD will not work. If you run EasyBCD with the PC currently booting in EFI. You will get this Warning Message.
    Installing some OS's in UEFI and some using Legacy BIOS-.jpg

    As you found out. Setting dual boot with Windows & Linux running in EFI mode, you'd need another boot manager such as rEFInd. With MBR is easy as mentioned above.

    I don't own a Laptop so I am not sure how the EFI firmware works with CSM enabled/disabled but with my desktop, it does support both EFI+MBR, meaning both will be listed in the boot menu whether My OS was installed using EFI or MBR.

    I don't think it is possible to dual boot with a mix between EFI and MBR even under Windows Environment. You either have both EFI or both MBR.
      My Computer


  5. Posts : 241
    Windows 10 Pro
    Thread Starter
       #5

    Thanks.
    I don't think my laptop supports both at the same time. I think you can choose either MBR or EFI.
    truly I got this message that you posted above in the image.
    So what I need to do now is to wipe my hard drive, and clean install everything on the MBR? (Which means no secure boot or fastboot, right?)

    *edit: My UEFI does not have secure boot option. why do I have UEFI then? Is it sort of synonym for GPT then?

    **Question: when I say "Legacy mode" it's the same as saying "MBR" right?
      My Computer


  6. Posts : 2,799
    Linux Mint 20.1 Win10Prox64
       #6

    Simply put: when installing Windows:
    UFI Firmware uses GPT (GUID Partition Table) Partition scheme
    Legacy BIOS uses MBR (Master Boot Record) partition scheme
      My Computer


  7. Posts : 241
    Windows 10 Pro
    Thread Starter
       #7

    topgundcp said:
    Simply put: when installing Windows:
    UFI Firmware uses GPT (GUID Partition Table) Partition scheme
    Legacy BIOS uses MBR (Master Boot Record) partition scheme
    Thank you!
    Since I do not have the knowledge of the in-depth software meaning of GUID Partition Table and Master Boot Record, I would like to know then, (if you can put it simple again): If I created Ubuntu and Windows in a GUID, and the 3rd Linux in MBR, is it possible that during installation of the third Linux, it recognized that I have the other 2 in UEFI and moved itself to the GUID and did not position itself in the MBR after it detected that?
      My Computer


  8. Posts : 34
    Linux
       #8

    Do not try to mix MBR and GPT/UEFI. It is asking for trouble. Just recreate your Linux usb stick with GPT/UEFI support, assuming that the linux distribution supports UEFI. All current *buntu flavors do.
    For Ubuntu 15.10 Unetbootin no longer works. Maybe rufus still does, I do not know. dd does work:
    Code:
    # dd if=<your iso file> of=/dev/sdb bs=1024
    assuming that /dev/sdb is your usb stick. I do not think the bs parameter matters very much.

    If the dd command scares you, you can have a look at https://help.ubuntu.com/community/Installation/FromUSBStick#mkusb_-_dd_image_of_iso_file_to_USB_device_safely
      My Computer


  9. Posts : 2,799
    Linux Mint 20.1 Win10Prox64
       #9

    Do not try to mix MBR and GPT/UEFI. It is asking for trouble
    Agreed and much easier using MBR as mentioned above.

    siepo said:
    . Just recreate your Linux usb stick with GPT/UEFI support, assuming that the linux distribution supports UEFI. All current *buntu flavors do.
    For Ubuntu 15.10 Unetbootin no longer works. Maybe rufus still does, I do not know. dd does work:
    Code:
    # dd if=<your iso file> of=/dev/sdb bs=1024
    assuming that /dev/sdb is your usb stick. I do not think the bs parameter matters very much.

    If the dd command scares you, you can have a look at https://help.ubuntu.com/community/Installation/FromUSBStick#mkusb_-_dd_image_of_iso_file_to_USB_device_safely
    Need not use Rufus nor dd. Just format the stick with FAT32, use Winzip/Winrar/7-zip to extract the content of the ISO to the root folder of the stick, open Disk Management to set "Active" then you can boot from it.
      My Computer


  10. Posts : 241
    Windows 10 Pro
    Thread Starter
       #10

    I don't know if it means that I mixed MBR with UEFI, maybe you can understand:
    I had in my BIOS the UEFI Enabled, and Legacy disabled, with 2 OS installed: Ubuntu and Windows 10.
    The 3rd Linux, was not detected in the UEFI boot menu, so I enabled Legacy, and it was detected, so I chose it from this menu that appears in the BIOS under Legacy boot options.
    Then the installation started. when it started, it did prompt me that I have Ubuntu installed, and what I'd like to do? I chose to install the boot loader inside /dev/sda2 (which later realized was Windows UEFI partition, and not the grub partition of Ubuntu), and from some reason, it did not cause any problems, and I now see all 3 OS's from the GRUB menu, and no problems.

    So I think that the other Linux does support UEFI, but my laptop's BIOS did not detected it on the menu of the UEFI boot options from some reason, and after I installed it when Legacy bios was enabled, it moved itself to the UEFI part. (I'm talking general terms, because as I said I do not really know what's going deeper like you guys, but maybe you can understand from my description)

    Thank you for the help
      My Computer


 

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