Cannot UEFI boot on another drive

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  1.    #1

    Cannot UEFI boot on another drive


    Hello,

    I am using a laptop with 2 drives. Lets call them Disk0 and Disk1.
    On both disk I have installed windows pro.
    I thought i could simply tell in the BIOS on which drive to boot but it did not work like that, so I decided to install AIOBoot and Clover on a Fat32 partition on Disk1. It helped me switch from one windows to another. Each time I was telling the AIOBoot to change the bootloader from Disk0 to 1 or 1 to 0 depending on what i needed.
    Recently I decided to encrypt disk0. It was stupid as I did not think about the clover bootloader - Clover did not see the disk0 anymore. Then I could not boot. I used a USB key to boot on the encrypted drive and decided to stop the encryption.
    Now I do not know what hapened but I am struggling to boot into the other disk1 and I get a bluescreen with an error of wdfilter.sys
    However I can still boot on the disk1. No idea why.
    Is there a way to have the disk1 booting. Is it a simple error because of wdfilter.sys?
      My ComputerSystem Spec

  2. bro67's Avatar
    Posts : 5,849
    Mac OS High Sierra 10.14.3 Beta (18D21c)
       #2

    You probably downloaded Clover legacy. The bootloader would go into its own FAT32 partition and the OS partitions would need to be GPT. You only need one bootloader if you wish to use them, but do not need, since Windows has its own bootloader built in. GRUB2 can cause issues.
      My ComputerSystem Spec

  3.    #3

    bro67 said: View Post
    You probably downloaded Clover legacy. The bootloader would go into its own FAT32 partition and the OS partitions would need to be GPT. You only need one bootloader if you wish to use them, but do not need, since Windows has its own bootloader built in. GRUB2 can cause issues.
    Thanks bro67. Where will the bootloader be then?
    I need a bit of theory please.

    If I have 2 different drives, I can have 2 bootloaders right?
    So if I have 2 windows drive, by default I should have 2 windows bootloaders?
    Are windows bootloader in a FAT32 partition? Is it in a partition or integrated in the NTFS one of the OS?
    How can I rebuild a bootloader on one of those drives?
      My ComputerSystem Spec

  4. bro67's Avatar
    Posts : 5,849
    Mac OS High Sierra 10.14.3 Beta (18D21c)
       #4

    You have one bootloader, regardless of how many OS's that you have installed on a single drive or multiple drives. The boot manager is not the boot loader vice-versa. You can have multiple boot managers, but only one boot loader.
    Last edited by bro67; 22 Jan 2019 at 16:27.
      My ComputerSystem Spec

  5.    #5

    bro67 said: View Post
    You have one bootloader, regardless of how many OS's that you have installed on a single drive or multiple drives.
    That isn't really true (although it is semantics). For example on my MacBook I have Windows, Syslinux, GRUB2 and whatever the MacOS one is called all of which are bootloaders (most are bootmanagers too). I have a dedicated bootmanager called rEFInd that looks to see it it can find any bootloaders on any connected disks and then gives a menu to choose between them.


    jbesclapez said: View Post
    I decided to install AIOBoot and Clover on a Fat32 partition on Disk1.
    I decided to encrypt disk0
    Now I do not know what hapened but I am struggling to boot into the other disk1
    However I can still boot on the disk1. No idea why.
    Is there a way to have the disk1 booting. Is it a simple error because of wdfilter.sys?
    I don't understand this. Can you boot disk1 or not? What is the "other disk1"? Disk0?

    If you overwrote (encrypted) your boot manager then your firmware will most likely still boot from the bootloader on the other disk. The bootmanager (or bootloader) that your firmware calls must be on unencrypted partition. It can then boot an encrypted volume if it has the means to decrypt it (which is how bitlocker works). If you have encrypted only Disk0 then whether Clover was on disk1 or disk0 then disk1 should still boot - either booting Clover or the Microsoft bootloader.

    Perhaps this explains what you are seeing but I'm confused with what is on which disk.

    There is some logic to it (see here) but not all manufacturers follow it. So if your firmware can't find whatever it booted last (this is stored in EFI Variables NVRAM usually) it may try to boot EFI/BOOT/bootx64.efi for example (this is the default) and if it doesn't find that try and boot EFI/Microsoft/Boot/bootmgfw.efi even though there is nothing in EFI specs about that particular name.

    I think your wdfilter.sys issue is most due to the partial encryption and I'd just reinstall rather than try and figure it out if that is an option.
      My ComputerSystem Spec

  6.    #6

    lx07 said: View Post
    That isn't really true (although it is semantics). For example on my MacBook I have Windows, Syslinux, GRUB2 and whatever the MacOS one is called all of which are bootloaders (most are bootmanagers too). I have a dedicated bootmanager called rEFInd that looks to see it it can find any bootloaders on any connected disks and then gives a menu to choose between them.


    I don't understand this. Can you boot disk1 or not? What is the "other disk1"? Disk0?

    If you overwrote (encrypted) your boot manager then your firmware will most likely still boot from the bootloader on the other disk. The bootmanager (or bootloader) that your firmware calls must be on unencrypted partition. It can then boot an encrypted volume if it has the means to decrypt it (which is how bitlocker works). If you have encrypted only Disk0 then whether Clover was on disk1 or disk0 then disk1 should still boot - either booting Clover or the Microsoft bootloader.

    Perhaps this explains what you are seeing but I'm confused with what is on which disk.

    There is some logic to it (see here) but not all manufacturers follow it. So if your firmware can't find whatever it booted last (this is stored in EFI Variables NVRAM usually) it may try to boot EFI/BOOT/bootx64.efi for example (this is the default) and if it doesn't find that try and boot EFI/Microsoft/Boot/bootmgfw.efi even though there is nothing in EFI specs about that particular name.

    I think your wdfilter.sys issue is most due to the partial encryption and I'd just reinstall rather than try and figure it out if that is an option.
    lx07 thanks for stepping in. It is not semantic, it is important for the global understanding. I have another laptop runing CLover UEFI with windows 10 and MacOSX. Clover seems the boot of all of them. You can only call ONE bootloader but this bootloader can read other ones...

    Regarding the rest of your message, I decrypted the disk. However, I totally understand your point in the second part of your post.

    I think I will do a reinstall then... However, if I install Win10 on disk1, where will the bootloader be located? If disk0 breaks, will it still boot on disk1 and if disk 1 breaks will it still boot on disk 0? Can I have the choice of bootloader to use in the UEFI bios? I used to have on the other pc Windows bootloader or Clover in the BIOS. I chose clover as from it, i could boot win and macOS.

    Thanks for your explanations
      My ComputerSystem Spec

  7.    #7

    We really need to see a screenshot of disk management to determine what is going on, rather than just blindly guessing.
      My ComputerSystem Spec

  8. bro67's Avatar
    Posts : 5,849
    Mac OS High Sierra 10.14.3 Beta (18D21c)
       #8

    Ix07 has Operating systems confused on what a Bootloader is. The BIOS/MBR Boot Process Mac OS Darwin used to use BootX with the PowerPC, now uses Boot.efi like Windows does. Only one bootloader can be used, which then goes to the Boot menu, to get input from the user as to what OS that they wish to load up or have automatically loaded.
    Attached Thumbnails Attached Thumbnails MBR-Boot-Sequence.png   Bootloader-Sequence.png   Bootloader-Flowchart.png  
    Last edited by bro67; 23 Jan 2019 at 16:08.
      My ComputerSystem Spec

  9.    #9

    bro67 said: View Post
    Ix07 has Operating systems confused on what a Bootloader is. The BIOS/MBR Boot Process Mac OS Darwin used to use BootX with the PowerPC, now uses Boot.efi like Windows does. Only one bootloader can be used to get input from the user as to what OS that they wish to load up or have automatically loaded.
    You would be entirely mistaken, which is not uncommon.
      My ComputerSystem Spec

  10. Kari's Avatar
    Posts : 15,636
    Windows 10 Pro
       #10

    Boot to Windows 10 on Disk 0. Check the drive letter for Windows partition on Disk 1. Let's say it's drive E:.

    Enter following command in elevated Command Prompt to add Windows on Disk 1 to boot menu:

    bcdboot E:\Windows

    Enter following command to make Windows on Disk 0 the default OS:

    bcdedit /default {current}

    That's it. From here on, your boot menu let's you choose which Windows to boot.

    Kari
      My ComputerSystem Spec


 
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