From: nowhere@never.at   
      
   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   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)