Dual boot

[Celso Viana]

Hi all,

You know if you can dual boot with GPT and BIOS disks on the same machine?

/dev/sdb GPT -> Windows 10
/dev/sda BIOS -> Fedora 23 x64

The machine only starts with Windows; not appear the boot menu

Thanks!

[Samuel Sieb]

On 05/28/2016 07:53 PM, Celso Viana wrote:
> You know if you can dual boot with GPT and BIOS disks on the same machine?
>
> /dev/sdb GPT -> Windows 10
> /dev/sda BIOS -> Fedora 23 x64
>
> The machine only starts with Windows; not appear the boot menu

You will have to get into the UEFI BIOS setup and make sure that the the 
boot menu is enabled and maybe a boot delay to make it easier to get to 
the boot menu.  Some BIOS allow you to switch from EFI to CSM mode in 
the boot menu.  If not, then you will have to switch it each time in the 
BIOS setup screen.

[Chris Murphy]

On Sat, May 28, 2016 at 8:53 PM, Celso Viana  wrote:
> Hi all,
>
> You know if you can dual boot with GPT and BIOS disks on the same machine?
>
> /dev/sdb GPT -> Windows 10
> /dev/sda BIOS -> Fedora 23 x64
>
> The machine only starts with Windows; not appear the boot menu

GPT is to MBR as UEFI is to BIOS. GPT is a partition scheme. BIOS is a
firmware type. So there's no such thing as a BIOS disk. But if I guess
that by BIOS you mean sda is an MBR drive, in which case this is not a
supportable configuration and you should reinstall Fedora so you get a
UEFI based installation, and sda is partitioned using GPT.

Many firmware do have a legacy option in the firmware setup, but you'd
have to switch legacy on to boot this particular installation you have
of Fedora; and switch it back to boot Windows. That's probably why
right now only Windows is booting.

[Ger van Dijck]

Op Sun, 29 May 2016 04:53:26 +0200 schreef Celso Viana  
:
> Hi all,
>
> You know if you can dual boot with GPT and BIOS disks on the same  
> machine?
>
> /dev/sdb GPT -> Windows 10
> /dev/sda BIOS -> Fedora 23 x64
>
> The machine only starts with Windows; not appear the boot menu
>
> Thanks!

Hi Celso ,

Do as follows : Secure Boot disabled
                   Load Legacy Option ROM enabled
                   Boot List Option Legacy

I had the same problen and after setting the values in the BIOS as above  
everything works fine.

Greetings,
   Ger van Dijck.

[Chris Murphy]

On Mon, May 30, 2016 at 5:43 AM, Ger van Dijck  wrote:
> Op Sun, 29 May 2016 04:53:26 +0200 schreef Celso Viana
> :
> > Hi all,
> >
> > You know if you can dual boot with GPT and BIOS disks on the same machine?
> >
> > /dev/sdb GPT -> Windows 10
> > /dev/sda BIOS -> Fedora 23 x64
> >
> > The machine only starts with Windows; not appear the boot menu
> >
> > Thanks!
>
> Hi Celso ,
>
> Do as follows : Secure Boot disabled
>                   Load Legacy Option ROM enabled
>                   Boot List Option Legacy
>
> I had the same problen and after setting the values in the BIOS as above
> everything works fine.

OK it's bad advice. If it works for you, fine, but I think it's bad
advice to suggest three things that are inappropriate for essentially
all use cases: secure boot does protect against known boot kit
malware; legacy option ROM has numerous known malware exploits; and
the legacy boot option is incompatible with booting Windows. So the
advice breaks Windows boot, which cannot boot in legacy mode because
it wasn't installed in legacy mode, and it makes everything less
secure without improving usability.

[Corey Sheldon]

On 06/04/2016 03:23 PM, Chris Murphy wrote:
> On Mon, May 30, 2016 at 5:43 AM, Ger van Dijck  wrote:
> > Op Sun, 29 May 2016 04:53:26 +0200 schreef Celso Viana
> > :
> > > Hi all,
> > >
> > > You know if you can dual boot with GPT and BIOS disks on the same machine?
> > >
> > > /dev/sdb GPT -> Windows 10
> > > /dev/sda BIOS -> Fedora 23 x64
> > >
> > > The machine only starts with Windows; not appear the boot menu
> > >
> > > Thanks!
> >
> > Hi Celso ,
> >
> > Do as follows : Secure Boot disabled
> >                   Load Legacy Option ROM enabled
> >                   Boot List Option Legacy
> >
> > I had the same problen and after setting the values in the BIOS as above
> > everything works fine.
>
> OK it's bad advice. If it works for you, fine, but I think it's bad
> advice to suggest three things that are inappropriate for essentially
> all use cases: secure boot does protect against known boot kit
> malware; legacy option ROM has numerous known malware exploits; and
> the legacy boot option is incompatible with booting Windows. So the
> advice breaks Windows boot, which cannot boot in legacy mode because
> it wasn't installed in legacy mode, and it makes everything less
> secure without improving usability.

If you must  leave one system in BIOS mode,   Get into BIOS Setup and
set  UEFI+CSM (or UEFI+Legacy on older boxes) and add / reinstall Fedora
with /boot & /biosgrub and the rest of your setup as usual.   As someone
else mentioned add a delay for booting (to allow for  selection of the
second OS).

----
Corey W. Sheldon
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Find me elsewhere: https://gist.github.com/linux-modder/ac5dc6fa211315c633c9

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