Re: Re-enable grub boot in UEFI (Windows took over it) [SOLVED]

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Hello Chris,


On Thu, 1 Feb 2018 13:25:14 -0700 Chris Murphy <lists@xxxxxxxxxxxxxxxxx> wrote:

> On Thu, Feb 1, 2018 at 10:13 AM, wwp <subscript@xxxxxxx> wrote:
> > Hello Chris,
> >
> >
> > On Thu, 01 Feb 2018 17:00:03 +0000 Chris Murphy <lists@xxxxxxxxxxxxxxxxx> wrote:
> >  
> >> You can to use efibootmgr for this. NVRAM boot entry is what changed, not
> >> the contents of the EFI System partition.
> >>
> >> efibootmgr -v
> >>
> >> Will list all entries and Boot Order. You need to use --bootorder to make
> >> sure the CentOS entry is first.  
> >
> > Interesting.. thanks for your reply!
> >
> > Too bad I never run this command when things were OK (in order to
> > compare), 'cause now, what it says doesn't mention anything that seem
> > related to the CentOS partition or I read wrong:
> >
> > BootCurrent: 0007
> > Timeout: 0 seconds
> > BootOrder: 0001,0002,0003,0004,0005,0006,0007
> > Boot0000* Windows Boot Manager  HD(1,GPT,a6b87338-9b9c-4a50-8fde-2447e8fdebb6,0x800,0xfa000)/File(\EFI\Microsoft\Boot\bootmgfw.efi)WINDOWS.........x...B.C.D.O.B.J.E.C.T.=.{.9.d.e.a.8.6.2.c.-.5.c.d.d.-.4.e.7.0.-.a.c.c.1.-.f.3.2.b.3.4.4.d.4.7.9.5.}....................
> > Boot0001* UEFI: A400 NVMe SanDisk 512GB, Partition 1    HD(1,GPT,a6b87338-9b9c-4a50-8fde-2447e8fdebb6,0x800,0xfa000)/File(EFI\Microsoft\Boot\bootmgfw.efi)..BO
> > Boot0002* Diskette Drive        BBS(Floppy,Diskette Drive,0x0)..BO
> > Boot0003* M.2 PCIe SSD  BBS(HD,P0: A400 NVMe SanDisk 512GB,0x0)..BO
> > Boot0004* USB Storage Device    BBS(USB,KingstonDataTraveler 3.0PMAP,0x0)..BO
> > Boot0005* CD/DVD/CD-RW Drive    BBS(CDROM,CD/DVD/CD-RW Drive,0x0)..BO
> > Boot0006* Onboard NIC   BBS(Network,Onboard NIC,0x0)..BO
> > Boot0007* UEFI: KingstonDataTraveler 3.0PMAP, Partition 1       PciRoot(0x0)/Pci(0x14,0x0)/USB(16,0)/HD(1,MBR,0x61f11812,0x800,0x737f800)..BO
> >
> > I don't know what 0001 and 0002 refer to exactly (there's only one SSD
> > drive in this laptop).  
> 
> For whatever reason the CentOS entry is missing.

I'd like to know the reason (not formally asking here), the 1st time it
happened it was because I booted in Windows, which is known to more or
less rewrite the boot entries (in case of updates, IIRC), but this time
it was not the case, I was attempting to boot a pmagic live USB drive..
UEFI killer? :-/


> Option 1:
> 
> A relatively easy cheat is to mount your root volume to /mnt and then search
> 
> grep efibootmgr /mnt/var/log/anaconda/program.log     ##this is the
> path and name on Fedora, not 100% certain on CentOS
> 
> And what you'll get back is a line that contains the efibootmgr
> command that was used during the installation. So you'll need to
> modify the forward slashes for it to work, something like this:
> 
> sudo efibootmgr -c -w -L CentOS -d /dev/sda -p 2 -l
> \\EFI\\redhat\\grub\\shimx64.efi
> 
> Option 2:
> 
> At least on Fedora 27 + Windows 10, this is what my ESP contains:
> 
> ├── EFI
> │   ├── Boot
> │   │   ├── bootx64.efi
> │   │   ├── fallback.efi
> │   │   └── fbx64.efi

(no fallback.efi here, but I presume fbx64.efi is a fallback too?)


> Those are Fedora installed default bootloaders. So if you wipe out all
> the NVRAM boot entries, these get used first. And when fallback.efi
> figures out that there isn't a proper NVRAM boot entry, it's supposed
> to insert one, just like the Option 1 command above does. You'll use
> 'efibootmgr -b XXXX -B' to delete them one by one; looks like you
> might be able to get away with just deleting 0001 and 0000. Of course
> it means the Windows boot entry is blown away, which might make you
> nervous - but the way it's supposed to work is the GRUB menu should
> have a Windows boot option in it, and you just pick that for booting
> Windows.
> 
> 
> I've mainly used option 1.

You were right, the initial efibootmgr command was in anaconda's log, I
could do, for the sake of the archives:

$ efibootmgr -c -w -L CentOS Linux -d /dev/nvme0n1 -p 1 -l \\EFI\\centos\\shim.efi
BootCurrent: 0007
Timeout: 0 seconds
BootOrder: 0008,0001,0002,0003,0004,0005,0006,0007
Boot0000* Windows Boot Manager
Boot0001* UEFI: A400 NVMe SanDisk 512GB, Partition 1
Boot0002* Diskette Drive
Boot0003* M.2 PCIe SSD
Boot0004* USB Storage Device
Boot0005* CD/DVD/CD-RW Drive
Boot0006* Onboard NIC
Boot0007* UEFI: KingstonDataTraveler 3.0PMAP, Partition 1
Boot0008* CentOS

And it simply works, I could restart the system and boot from grub
(which proposes to boot to Windows too, grub is a good boy).

A huge thanks to you, Chris, I owe you one.


Regards,

-- 
wwp

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