From: "Thomas Schmitt" <scdbackup@gmx.net>
To: bug-xorriso@gnu.org
Cc: guix-devel@gnu.org
Subject: Re: ISO installer image: GPT versus MBR partitions
Date: Sun, 21 Apr 2019 14:27:10 +0200 [thread overview]
Message-ID: <36026727461461023450@scdbackup.webframe.org> (raw)
In-Reply-To: <20190421115606.7mi6rrawp2spziev@pelzflorian.localdomain>
Hi,
i wrote:
> > ... 3f 0b
> > ... 40 0b
> > ... == ==
Florian Pelz wrote:
> Why is 0b underlined?
Too much enthusiasm on my side.
> OK, so I just wrote the Guix git master with ludo’s reproducibility
> patches to a USB drive (boot gets stuck again) and then did:
> sudo dd if=/dev/sdc2 of=mysdc2.img
> When I open it with ghex, I find at position 446:
> 80 00 00 04 01 24 4f 00 00 00 00 80 16 00 00 00
Pinching eyes ...
Bootable flag is set.
Start C/H/S is 4/0/0. (x/y/1 is usual)
Partition type is 1.
End C/H/S is 1/36/15.
Start LBA is 0x80000000 = 2,147,483,648.
Block count is 0x16 = 22.
So what ever did you do to this mysdc2.img ?
> I change it to
> 80 00 02 00 01 01 12 4f 01 00 00 00 3f 0b 00 00
> I dd the changed mysdc2.img back to /dev/sdc2.
>
> Now it boots. :)
Start C/H/S is 0/0/2.
Partition type is 1.
End C/H/S ... i'm getting too old for decoding MBR C/H/S bit fields.
Start LBA is 1.
Block count is 0x0b3f = 2879.
So Start LBA 0 is indeed the trigger of the problem.
As soon as the partition entry does not point to its hosting block any
more, the (now very probable) loop in EFI cannot happen.
> Strangely, I now have only one entry “GRUB 2.02” in
> the boot selection, but “EFI Boot” (or what it was called) is gone.
What do you see if the partition entry is zeroized entirely ?
(Elsewise i refer to the Futurama quote in my previous mail.)
> Is it a good
> idea to add -k to mformat in grub-mkrescue for the upcoming Guix 1.0
> release (even though you don’t like it)?
We need to ask at grub-devel. I have begun to compose a mail.
You will be Cc-ed.
Does guix-devel want to be Cc-ed ?
New mail:
> MacBook Pro (13-inch, Mid 2010)
> Model Name: MacBook Pro
> Model Identifier: MacBookPro7,1
> Boot ROM Version: MBP71.003F.B00
> SMC Version (system): 1.62f7
I will put this into my mail to grub-devel.
> Serial Number ...
... but this only if asked for.
Back to old mail:
> Or should mformat be patched instead? Could any of
> this be upstreamed?
That's why i asked Ludovic about our chances with mtools upstream.
I would propose an option to write the usual pseudo-MBR but without that
partition entry.
(Well, maybe somebody there can even remember why a partition entry
is made by default.)
> What about your MBR repacking?
I will create an option for zeroizing bytes 446 to 461 of the EFI image.
When the dust has settled here, i will ask Ludovic for preparing the
ISO production code for a run with libisoburn's wrapper script
frontend/grub-mkrescue-sed.sh for MBR-only.
At that occasion, the EFI image repairer could be tested, too.
The script has a mode "original" which does not change the xorriso
options submitted by grub-mkrescue. So it produces original GPT.
(It's original purpose is spying on grub-mkrescue's xorriso options.)
> I just doing what I’m told, but I
> don’t quite understand what I’m doing here.
We had a wild ride over boot sectors and partition tables.
I collect my knowledge in libisofs file doc/boot_sectors.txt .
At days when our web certificates are valid, it is available at
https://dev.lovelyhq.com/libburnia/libisofs/raw/master/doc/boot_sectors.txt
Hah. Bug #4. No doc/boot_sectors.txt in libisofs tarball.
But it is in GNU xorriso's tarball:
https://fossies.org/linux/misc/xorriso-1.5.1.tar.gz/xorriso-1.5.1/doc/boot_sectors.txt
For completeness, a reserve address for my grub-mkrescue-xorriso wrapper:
https://sources.debian.org/src/libisoburn/1.5.0-1/frontend/grub-mkrescue-sed.sh
Have a nice day :)
Thomas
next prev parent reply other threads:[~2019-04-21 12:24 UTC|newest]
Thread overview: 78+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20190415165451.dpzngealeisbibc7@pelzflorian.localdomain>
[not found] ` <1582867226375139246@scdbackup.webframe.org>
2019-04-16 9:57 ` bug#33639: ISO installer image is broken on i686 Gábor Boskovits
2019-04-16 13:40 ` ISO installer image: GPT versus MBR partitions (was bug#33639) Thomas Schmitt
2019-04-16 16:32 ` pelzflorian (Florian Pelz)
2019-04-16 17:57 ` ISO installer image: GPT versus MBR partitions Thomas Schmitt
2019-04-16 19:55 ` pelzflorian (Florian Pelz)
2019-04-16 20:31 ` pelzflorian (Florian Pelz)
2019-04-16 21:15 ` Thomas Schmitt
2019-04-17 8:59 ` pelzflorian (Florian Pelz)
2019-04-17 10:23 ` Thomas Schmitt
2019-04-17 10:30 ` pelzflorian (Florian Pelz)
2019-04-17 15:51 ` Thomas Schmitt
2019-04-17 22:35 ` pelzflorian (Florian Pelz)
2019-04-18 6:32 ` Thomas Schmitt
2019-04-18 7:00 ` Thomas Schmitt
2019-04-18 7:07 ` pelzflorian (Florian Pelz)
2019-04-18 8:13 ` Thomas Schmitt
2019-04-18 12:19 ` pelzflorian (Florian Pelz)
2019-04-18 13:50 ` Thomas Schmitt
2019-04-18 21:28 ` Thomas Schmitt
2019-04-19 7:29 ` pelzflorian (Florian Pelz)
2019-04-19 8:03 ` pelzflorian (Florian Pelz)
2019-04-19 9:01 ` Thomas Schmitt
2019-04-19 9:39 ` pelzflorian (Florian Pelz)
2019-04-19 10:58 ` Thomas Schmitt
2019-04-19 14:57 ` pelzflorian (Florian Pelz)
2019-04-19 11:30 ` pelzflorian (Florian Pelz)
2019-04-19 18:33 ` pelzflorian (Florian Pelz)
2019-04-19 19:23 ` Thomas Schmitt
2019-04-20 10:26 ` pelzflorian (Florian Pelz)
2019-04-20 10:50 ` Thomas Schmitt
2019-04-20 11:16 ` Thomas Schmitt
2019-04-20 11:29 ` Thomas Schmitt
2019-04-20 14:23 ` Thomas Schmitt
2019-04-20 14:54 ` pelzflorian (Florian Pelz)
2019-04-20 15:17 ` pelzflorian (Florian Pelz)
2019-04-20 15:33 ` pelzflorian (Florian Pelz)
2019-04-20 16:32 ` Thomas Schmitt
2019-04-21 7:58 ` pelzflorian (Florian Pelz)
2019-04-21 9:35 ` Thomas Schmitt
2019-04-21 11:10 ` pelzflorian (Florian Pelz)
2019-04-21 11:16 ` Thomas Schmitt
2019-04-21 11:56 ` pelzflorian (Florian Pelz)
2019-04-21 12:27 ` Thomas Schmitt [this message]
2019-04-21 14:11 ` pelzflorian (Florian Pelz)
2019-04-21 14:36 ` Thomas Schmitt
2019-04-22 13:11 ` Thomas Schmitt
2019-04-23 16:40 ` pelzflorian (Florian Pelz)
2019-04-23 17:23 ` Thomas Schmitt
2019-04-17 12:24 ` Ludovic Courtès
2019-04-17 13:42 ` pelzflorian (Florian Pelz)
2019-04-23 18:14 ` Thomas Schmitt
2019-04-23 19:50 ` pelzflorian (Florian Pelz)
2019-04-23 20:18 ` Thomas Schmitt
2019-04-23 21:43 ` pelzflorian (Florian Pelz)
2019-04-24 6:56 ` Thomas Schmitt
2019-04-24 9:13 ` pelzflorian (Florian Pelz)
2019-04-24 10:34 ` Thomas Schmitt
2019-04-24 22:13 ` Danny Milosavljevic
2019-04-25 7:07 ` Thomas Schmitt
2019-04-25 9:45 ` pelzflorian (Florian Pelz)
2019-04-25 13:44 ` Thomas Schmitt
2019-04-25 14:59 ` Danny Milosavljevic
2019-04-25 16:22 ` Thomas Schmitt
2019-04-25 17:55 ` Danny Milosavljevic
2019-04-25 18:46 ` Thomas Schmitt
2019-04-25 19:01 ` Danny Milosavljevic
2019-04-25 16:34 ` Ludovic Courtès
2019-04-26 11:34 ` pelzflorian (Florian Pelz)
2019-04-26 14:41 ` Ludovic Courtès
2019-04-26 15:30 ` pelzflorian (Florian Pelz)
2019-04-26 13:57 ` Thomas Schmitt
2019-04-27 13:20 ` Ludovic Courtès
2019-04-27 16:24 ` Thomas Schmitt
2019-04-28 12:53 ` Ludovic Courtès
2019-04-25 11:49 ` pelzflorian (Florian Pelz)
2019-04-25 15:09 ` Thomas Schmitt
2019-04-25 15:58 ` pelzflorian (Florian Pelz)
2019-04-25 16:40 ` Thomas Schmitt
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