Re: debian-installer for mac
the original post I made speculates there could be improvement for
booting UEFI on certain models given that for a MacMini 2012 model there
is no way debian will boot in "UEFI" mode.
There is probably a "glitch" or strict-policy set in this MacMini's UEFI
firmware preventing debian seeing the UEFI variables.
^ This all changes just by using RUFUS OR "dd"(dumping) the ISO
filesystem from one of the debian isos...
There's a hybridness feature of these ISOs, but for some reason creating
a GPT-header iso image allows the debian installer to perform a proper
installation of
------> """grub-efi""" <-----
and not grub-pc(bios) ...
If I do not specificially set just a GPT-header for the iso(and place it
on a usb-boot stick), the MacMini 2012 will not boot, as debian will try
to install grub-pc(bios), and it will complain about not being able to
install grub, reboot the machine in stuck loops, and so on.
The nice thing here, is I am not using "gptsync" or any crazy MBR+GPT
hybrid nonsense for the internal SSD disk of this MacMini.
Once debian finishes installing(UEFI-mode), it can boot straight on its own.
"efibootmgr" shows debian right at the top, and it has bumped the macos
down one.
The intructions for any Mac or Windows user is very simple of a task to
have the debian-installer boot successfully: (that is in UEFI-mode)
1) Download rufus on Mac or Windows, and then use the program to choose
GPT-header for the USB stick, and that's pretty much it.
2) Boot and expect your Mac UEFI to be happy it can see a GPT-header
from the usb stick...
The nice thing here, is that mac users do not have to do any special
"gptsync" task or dangerous hybrid MBR+GPT syncs for their internal
drives, which can render data loss if not done correctly... this problem
goes away entirely..
I believe Apple's UEFI firmware breaks the specs it is supposed to allow
-- even though it's an MBR-header on the iso, iirc the UEFI firmware is
supposed to still to grant installers in accessing UEFI variables..
maybe Apple is breaking exactly this.
-- and as many know it's not possible to disable CSM/BIOS on a mactel..
.. though there is also problems I think similarly on PCs... to mitigate
the UEFI-detection problem there is the option to disable CSM/BIOS and
have "strict UEFI-only".
so force the Mac to see the GPT-header only, and that works very well
afaict.
fwiw, I also tested making the USB-boot stick with just Linux without
the need for rufus.
.. as long as there is a GPT-header, the debian-installer boots as
expected in UEFI-mode always, and never in BIOS-mode, as it's
installer-boot menu shows. "BIOS" or "UEFI" in parenthesis.
Here are the few ways I tested making the debian-instaler:
1) GPT-header made with Rufus on Windows
2) Using loopbacks against the iso image, and creating a full GPT-header
USB, then cloning the iso-loopback directly onto the USB stick. <<<
this means that I have tested the USB-stick with the
"GPT-Backup-reserved table" at the end of the disk
3) creating a brand new ISO image with a GPT-header only, and then
dumping that ISO onto a usb.
^ last one 3) wouldn't have a GPT-backup-header on the usb media itself
(though the iso-image I made would have it far away somewhere in the
middle of the disk)..
I wanted to make sure 2) can boot as well as 3), so I took the extra
time to use "gdisk" to wipe out any end-of-disk GPT reserve tables, MBR
tables, etc...
and so far the tests have always been very quick to verify.
A Mac Mini 2012 always boots into UEFI-mode with the debian-installer as
long as there is a GPT-header... never when it sees a DOSMBR header..
gdisk was used to remove any GPT-backup reserve table on each test... so
I can distinguish whether having or lacking the GPT-backup table made a
difference.
^ It doesn't... so this is important, because essentially I can just
dump the ISO (that containst the GPT-header), and not worry about there
not being a backup-GPT table for this MacMini to process without any
further issues.
So after-all 2) works just as well as 3)..
And so by that, this means, no special tool would be required to have
this placed on a USB directly ...
... for those stubborn Macs like this one(Mac Mini 2012), it is always
looking for a GPT-header exclusively for it to grant UEFI-mode for the
installer, otherwise debian will require extra foot-work around with
things like "Refind", and having to deal with an "MBR" table.
^ By having the debian-installer boot into UEFI-mode, dual-booting this
with a macos was extremely easy:::
In fact here is my current setup::
- Two disks: One disk has 50% of it occupied by Catalina MacOS..
- The same two disks, I have Debian 11.1 md-raid1 spread across both of
these disks.
If I want to boot MacOS, I just hold the option key and select Macos.
If I want to boot into Debian, I just hit the power-button and it boots
directly into Debian.
No refind or extra magic is required.
I don't know if there are other macs that have this problem -- but it
really does get rid of the complexiity of having to deal with extra
tools like Refind or maybe even go as far as using the ancient "gptsync".
Dual-booting a Mac is very easy, only if you can boot the
debian-installer in UEFI-mode..
It actually turned out much better than I expected.
I recall trying a debian-install on this years ago (I barely used this
mac-mini ;-) -- and had to work around refind, gptsync, it was an
absolute nightmare.
How common is it to have Debian install with "grub-pc" rather than
"grub-efi" when it comes to Mactels?
I'm kind of interested. .. otherwise this information is definitely
worth sharing.
It is pretty much two mouse clicks with Rufus, and that sovles the
problem of having Debian boot into UEFI mode on Mactels.
It's that simple.
thanks for everyone answering, it was great feedback.
On 2021-10-24 2:20 p.m., Nicholas D Steeves wrote:
"Andrew M.A. Cater" <amacater@einval.com> writes:
As mentioned on debian-user: the debian-11.1.0-amd64-netinst.iso or the
debian-11.1.0-amd-DVD-1.iso are the appropriate ones to use.
The debian-mac images are for a couple of specific models from 2008/2009
which had problems recognising El Torito images.
Oh yeah! I remember having to ask about this for a 2014 installation I
did on a 2012 MBP. Has it not been documented yet?
Seems like the website and installation guide could benefit from bug
reports requesting documentation of this fact. I believe it's worth the
effort, because recent macOS versions don't work well with older Apple
hardware.
Regards,
Nicholas
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