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Re: And yet another UEFI/BIOS question: Work on both.



Thank you for the 15 seconds of time that you spent. But that page that you linked to is useless.

Wayne Sallee
Wayne@WayneSallee.com
http://www.WayneSallee.com

On 09/23/2018 12:18 PM, Patrick Bartek wrote:
On Sun, 23 Sep 2018 10:58:54 -0400
Wayne Sallee <Wayne@WayneSallee.com> wrote:

What do you recommend for setting up a system that will boot in
either UEFI or BIOS mode, so if it is moved back and forth between
UEFI and BIOS, it will boot every time?
I recommend you learn how to use Google or DuckDuckGo, etc. searches for
such basic queries. The following was the first result in the list of my
search. Total time spent: about 15 seconds.

https://truthseekers.io/everything-you-need-to-know-to-dual-boot-uefi-gpt-bios-mbr-partitions-swap-space-and-more/

Also, read up on "chainloading."

B

Wayne Sallee
Wayne@WayneSallee.com
http://www.WayneSallee.com



On 09/21/2018 02:21 PM, Pascal Hambourg wrote:
Le 21/09/2018 à 08:34, steve a écrit :
Le 20-09-2018, à 20:25:26 +0200, Pascal Hambourg a écrit :
You don't need to convert anything. UEFI can use DOS partition
tables.
I know since that's what I'm currently doing.
Doing what ?
Using msdos partition tables.
This is irrelevant because until now you were booting Debian in
legacy (BIOS) mode.
I am not talking about you doing anything. I am saying that
native UEFI boot (NOT legacy boot) can use a disk with a DOS
partition table, provided that it has an EFI system partition (Id
0xef).
Isn't it ef00?
No. ef00 is a gdisk specific mnemonic for the EFI system partition
type identifier in a GPT partition table. The actual GUID is
C12A7328-F81F-11D2-BA4B-00A0C93EC93B. (0x)ef is the partition type
identifier for an EFI system partition in a DOS partition table.
Because what I finally did is install a fresh Debian on another
device (using GPT) and the ACPI errors still were there.
In legacy mode (with a BIOS boot partition) or EFI mode (with an
EFI system partition) ?
I used the opportunity of having another Debian to convert my sda
disk to GPT tables, and change the BIOS setting to UEFI only (just
for the sake of it). So all my disk have a GPT partition table
except for the 3 ones for the RAID1 array. Not sure whether I can
use the same manipulations to convert them to GPT also. But since
they work fine, I might leave it as it is.
You can, but IMO it provides little value. GPT is useful in the
following cases :
- disk bigger that 2 TiB
- more that 4 partition without the extended/logical partition
kludge
- need to use PARTLABEL or PARTUUD (but RAID uses its own UUID)
- system disk for Windows in EFI mode

AFAICS none of these conditions apply to your RAID disks. However I
noticed that 2 out of the 3 RAID partition on each disk are logical
partitions. This is not necessary if there are only 3 partitions
per disk. So in order to get rid of the extended partition kludge,
you could either convert the logical partitions into primary
partitions or convert the partition table to GPT.




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