Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]


Groups > alt.os.development > #18653

Re: Secrets on UEFI GPT

From wolfgang kern <nowhere@never.at>
Newsgroups alt.os.development
Subject Re: Secrets on UEFI GPT
Date 2024-02-13 08:40 +0100
Organization A noiseless patient Spider
Message-ID <uqf6e5$209vf$1@dont-email.me> (permalink)
References (1 earlier) <up2g4d$3ajrq$1@dont-email.me> <uq5cvj$2lrhf$1@dont-email.me> <uq5hr0$2mmdt$1@dont-email.me> <uq5t74$2op35$1@dont-email.me> <uqf0cq$1vdn9$1@dont-email.me>

Show all headers | View raw


On 13/02/2024 06:57, Paul Edwards wrote:
> On 10/02/24 03:08, wolfgang kern wrote:
> 
>> if you have access to any UEFI GPT machine can you please copy me a 512
>> byte hexdump of LBA_1 ?
> 
> I checked the replies but didn't see anyone
> post the requested hexdump.
> 
>> this would answer all my open questions on GPT.
> 
> Ok, I don't know anything about GPT, but what I do
> know is that my Chinese computer (with Zhaoxin
> processor) that has Kylin OS installed has UEFI
> enabled, and if I switch to legacy, it no longer
> boots.
> 
> But legacy boots PDOS, including from USB stick.
> 
> So after booting PDOS I have done an xychop from
> drv81: for 1024 bytes, and here it is:


thanks a lot:
I convert it to explain what's where
LBA_0_MBR
0000..     all zero
01b8 0c 21 27 11    ;mark from formatting
01bc 00 00
01be d3              it's bootable but an unusual value
01bf 14 02 00       ;boot sector start CHS
01c2 EE             ;this is an EFI partition
01c3 FF FF FF       ;last CHS sector (>> here)
01c6 01 00 00 00    ;GPT is on LBA_1 yet
01ca 3b 9e 12 af    ;total disk size (sectors)
   2'937'232'955 sectors are 1.5 TB with 512 byte sectors
01ce ...            ;all zero
01fe 55 aa
----------
LBA_1 (GPT)
0200 45464920 50415254  ;"EFI PART"
0208 00000100           ;version 1.0020c 5C000000           ;header size
0210 9D526FFC           ;CRC
0214 00000000           ;align filler
0218 01000000_00000000  ;header copy LBA (points to itself here)
0220 AF129E3B_00000000  ;backup LBA      (the last on disk here)
0228 22000000_00000000  ;first usable LBA (aka wast count)
0230 8E129E3B_00000000  ;last usable LBA (wast 32 at the end too?)
0238 6F892CDF_A452F145  ;DISK GUIDE (now guess where this come from)
0240 96E465FA_F34F6C40  ; _"_
0248 02000000 00000000  :LBA start of GPT entries array (always 2)
0250 80000000           ;number of GPT entries (128 here ???)
0254 80000000           ;size of a GPT entry (128 as usual)
0258 224BCEB6           ;CRC32 of partition array
-------------           ;end of header
025c ..3ff              ;all zero

> I assume that is GPT, but since UEFI can boot from MBR
> (as I mentioned before), maybe it isn't.

yeah it is.

> I haven't attempted to analyze it.

my pleasure to do such:)
and it confirms my ideas on how it shall look like.
__
wolfgang

Back to alt.os.development | Previous | NextPrevious in thread | Next in thread | Find similar | Unroll thread


Thread

UEFI GPT wolfgang kern <nowhere@never.at> - 2024-01-20 05:16 +0100
  Re: UEFI GPT Paul Edwards <mutazilah@gmail.com> - 2024-01-20 23:44 +0800
    Re: UEFI GPT wolfgang kern <nowhere@never.at> - 2024-01-21 00:56 +0100
      Re: UEFI GPT Paul Edwards <mutazilah@gmail.com> - 2024-01-21 10:04 +0800
  Re: UEFI GPT wolfgang kern <nowhere@never.at> - 2024-01-27 09:50 +0100
    Re: Secrets on UEFI GPT wolfgang kern <nowhere@never.at> - 2024-02-09 15:31 +0100
      Re: Secrets on UEFI GPT Herbert Kleebauer <klee@unibwm.de> - 2024-02-09 16:54 +0100
        Re: Secrets on UEFI GPT wolfgang kern <nowhere@never.at> - 2024-02-09 20:08 +0100
          Re: Secrets on UEFI GPT Herbert Kleebauer <klee@unibwm.de> - 2024-02-09 22:03 +0100
            Re: Secrets on UEFI GPT wolfgang kern <nowhere@never.at> - 2024-02-10 05:16 +0100
              Re: Secrets on UEFI GPT wolfgang kern <nowhere@never.at> - 2024-02-10 09:11 +0100
          Re: Secrets on UEFI GPT Paul Edwards <mutazilah@gmail.com> - 2024-02-13 13:57 +0800
            Re: Secrets on UEFI GPT wolfgang kern <nowhere@never.at> - 2024-02-13 08:40 +0100
              Re: Secrets on UEFI GPT wolfgang kern <nowhere@never.at> - 2024-02-13 08:45 +0100
      Re: Secrets on UEFI GPT scott@slp53.sl.home (Scott Lurndal) - 2024-02-09 15:59 +0000
        Re: Secrets on UEFI GPT wolfgang kern <nowhere@never.at> - 2024-02-09 20:12 +0100
          Re: Secrets on UEFI GPT wolfgang kern <nowhere@never.at> - 2024-02-09 20:30 +0100
            Re: Secrets on UEFI GPT scott@slp53.sl.home (Scott Lurndal) - 2024-02-09 20:37 +0000
              Re: Secrets on UEFI GPT wolfgang kern <nowhere@never.at> - 2024-02-10 05:25 +0100
                Re: Secrets on UEFI GPT cross@spitfire.i.gajendra.net (Dan Cross) - 2024-02-10 19:21 +0000
                Re: Secrets on UEFI GPT wolfgang kern <nowhere@never.at> - 2024-02-11 02:00 +0100
          Re: Secrets on UEFI GPT scott@slp53.sl.home (Scott Lurndal) - 2024-02-09 20:34 +0000
            Re: Secrets on UEFI GPT wolfgang kern <nowhere@never.at> - 2024-02-10 05:23 +0100
              Re: Secrets on UEFI GPT "Alexei A. Frounze" <alexfrunews@gmail.com> - 2024-02-09 20:45 -0800
                Re: Secrets on UEFI GPT wolfgang kern <nowhere@never.at> - 2024-02-10 08:59 +0100
                Re: Secrets on UEFI GPT cross@spitfire.i.gajendra.net (Dan Cross) - 2024-02-11 01:11 +0000
                Re: Secrets on UEFI GPT wolfgang kern <nowhere@never.at> - 2024-02-11 07:04 +0100
                Re: Secrets on UEFI GPT cross@spitfire.i.gajendra.net (Dan Cross) - 2024-02-11 20:08 +0000
                Re: Secrets on UEFI GPT wolfgang kern <nowhere@never.at> - 2024-02-11 22:03 +0100
                Re: Secrets on UEFI GPT Andy Valencia <vandys@vsta.org> - 2024-02-11 14:38 -0800
                Re: Secrets on UEFI GPT wolfgang kern <nowhere@never.at> - 2024-02-12 01:48 +0100
      Re: Secrets on UEFI GPT JJ <jj4public@outlook.com> - 2024-02-10 20:10 +0700
        Re: Secrets on UEFI GPT wolfgang kern <nowhere@never.at> - 2024-02-10 17:05 +0100
        Re: Secrets on UEFI GPT wolfgang kern <nowhere@never.at> - 2024-02-14 06:37 +0100

csiph-web