Windows 7 and UEFI Compatibility


  1. Posts : 40
    Windows 7 64 bit
       #1

    Windows 7 and UEFI Compatibility


    I am sure this has been asked before.

    I have Windows 7 installed on one of my machines using Legacy boot. If I change the boot mode to UEFI, will windows 7 still run?
      My Computer


  2. Posts : 623
    Windows 7 Pro 64-bit / Windows 10 Pro 64-bit (dual boot)
       #2

    If the BIOS was in legacy mode before Windows 7 was installed, do not change the BIOS to UEFI mode.
    If you do, Windows 7 will not load.

    Why are you wanting to change the BIOS to UEFI mode?
      My Computer


  3. Posts : 7,074
    Windows 7 HP 64
       #3

    A drive can be initialized as MBR or GPT.
    Windows 7 can be installed as Legacy on a MBR drive or as UEFI on a GPT drive.
    As Legacy-MBR drive has a different boot sequence of UEFI - GPT drive you can't just change the boot type on BIOS.
    You have to:
    - Convert the drive from Legacy-MBR to UEFI - GPT using a Win 10 USB installation drive and run mbr2gpt.exe from a CMD window. (don't try to convert without making a drive image as a backup)
    - After conversion you set BIOS to boot as UEFI

    I can guide you on the conversion.
    I need to see a full Disk Manager (C:\Windows\System32\diskmgmt.msc) image
    Disk Management - Post a Screen Capture Image
      My Computers


  4. Posts : 6,214
    Windows 7 Ultimate x64
       #4

    Hiren's BootCD PE has disk tools like, DiskGenius or Macrorit Partition Expert that can convert MBR to GPT. Download | Hiren's BootCD PE


    What's the difference between Hiren's BootCD PE and a full blown Windows 10 disk? Well, Hiren's is smaller for one. It's also a PE (preinstallation Environment) live OS of Windows 10 for modern use in BIOS or UEFI. So you don't have to burn some 4+ GB of data to a USB drive or what ever. I use Ventoy to boot Hiren's. You just format the USB drive with Ventoy and quite literally copy/paste the Hiren's iso file on the Ventoy USB formatted drive. Boot the drive like you'd do to install an OS and Ventoy will show a menu to select what you'd like to boot. If you just have the one Hiren's iso file on the drive then that'll be all you can boot of course. You could copy/paste many iso files to the Ventoy USB formatted drive and pick from those to boot from withen Ventoy's menu. One of my Ventoy formatted drives has Hiren's alone with Memtest86.


    Ventoy

    - - - Updated - - -

    I just want to add here that unless you need to use hard drives that are larger than 2 TB, you don't need a GPT partition scheme and as a consequence, full blown UEFI in replace of BIOS. That's only if your BIOS supports legacy BIOS and UEFI like mine does. Now-a-days it's UEFI or the highway. Well, here's a problem with that. With Windows 8 on up there's something called WPBT (Windows Platform Binary Table) withen UEFI that can be used for rootkit like behavior. Read here and here.

    Also, UEFI has its very own richer network stack.

    Also see here.

    There are alternative BIOS' but mostly geared towards Linux.


    Here's a little Info. on the network stack in some of the best English ever.. Networking Features under the UEFI shell - YouTube

    cURL like a real hacker... Networking Features under the UEFI shell - YouTube (Regarding the low entropy with UEFI and lack of a "real" RNG, just "cURL" this website.... LOL RANDOM.ORG - Introduction to Randomness and Random Numbers)

    To think hospitals use Windows 10 and are prime target for zeroday ransomware...
    Last edited by F22 Simpilot; 17 Aug 2022 at 08:55.
      My Computer


  5. Posts : 40
    Windows 7 64 bit
    Thread Starter
       #5

    flavallee said:
    If the BIOS was in legacy mode before Windows 7 was installed, do not change the BIOS to UEFI mode.
    If you do, Windows 7 will not load.Why are you wanting to change the BIOS to UEFI mode?
    I was curious as, all of my other machines with Win 10 are UEFI except my dual boot PC. Win 7 is in the D drive partition and Win 10 "WAS" C drive partition before it crashed and burned. I was wondering if I changed it to UEFI before I re-install I was curious how win 7 would react.

    - - - Updated - - -

    F22 Simpilot said:
    Hiren's BootCD PE has disk tools like, DiskGenius or Macrorit Partition Expert that can convert MBR to GPT. Download | Hiren's BootCD PE.
    My Hiram's Boot CD is as old as the hills, should I download the latest?
      My Computer


  6. Posts : 7,074
    Windows 7 HP 64
       #6

    If you use one of those software's to convert a MBR to GPT it won't boot. Only mbr2gpt.exe will convert MBR to GPT and create a EFI Fat32 partition (required to boot from a GPT drive)
      My Computers


  7. Posts : 6,214
    Windows 7 Ultimate x64
       #7

    Now that I did not know. I found another program that supposedly does that, but I'm assuming Windows' tool of MBR2GPT would be more applicable and straight forward without proprietary nonsense.



    My Hiram's Boot CD is as old as the hills, should I download the latest?
    Yes, if you plan on using Hiren's for PC diagnostics or what ever then I'd be more inclined to use the newer version which uses a Windows 10 PE and updated tools. However, you might want to keep the older version if it's XP PE. I don't think you can download that version anywhere. Something like that would come in handy for older computers that ran XP I suppose. I used something called UBCD way back in the day with XP. Still have that disk in a CD case. Ultimate Boot CD - Overview

    Again, you can format a USB drive with Ventoy and just copy/paste the iso right to the drive. When you boot Ventoy you have a menu from which to chose which OS you would like to boot from. So you could have Memtest86, UBCD and Hiren's all one one drive... Not sure if you can format optical media with Ventoy. Something I've been meaning to read about and/or try. Reason why you might want to use optical media is that depending on the optical type and natural of the PC being worked on, nothing can write to your source media... Great for looking for malware or whatever.

    - - - Updated - - -

    Wow, first release was in 2003. Ultimate Boot CD - Version History

    - - - Updated - - -

    Oops! I used UBCD4Win! Not UBCD which is Linux based. LOL UBCD for Windows
      My Computer


 

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