From: nospam@needed.invalid   
      
   On Mon, 12/16/2024 8:16 AM, Dan Purgert wrote:   
   > On 2024-12-15, bad sector wrote:   
   >>   
   >> Since Intel have decided to fianally kill legacy BIOS in 2025 I have no   
   >> choice left. Knowing this day would come I've already created an EFI #1   
   >> partition, formatted with   
   >>   
   >> # mkfs.fat -F 32 /dev/sda1   
   >> [...]   
   >> My current motherboard supports Legacy BIOS only but I'm getting a new   
   >> board that supports EFI (only I think). How do I get the new motherboard   
   >> started up using my existing boot disk above?   
   >>   
   >> What happens when the disk fails? What's the BIOS and boot recovery   
   >> after I restore all partitions form images? Can I also keep an image of   
   >> the EFI partition and run again with that after a recovery?   
   >   
   > The disk fails.   
   >   
   > The "EFI System Partition" isn't really all that functionally different   
   > than the MBR of HDD on a BIOS-boot computer.  I *BELIEVE* you have to   
   > specifically format this as "EFI System Partition" instead of just FAT32   
   > (but I've never done it manually).   
   >   
   > I *BELIEVE* that this system partition is required to be stuffed   
   > somewhere within the first 2 TiB of a GPT-formatted drive, such that it   
   > is backwards compatible with MBR.   
   >   
   > Primary UEFI configuration (e.g. date/time, hardware config, etc.) all   
   > lives on battery-backed RAM of some sort or other, same as it always has   
   > under BIOS.   
      
   The GPT table has two kinds of numbers in it   
      
      GUID which functions as a block ID   
      
      GUID which functions as a partition type declaration   
      
   In Linux GDisk, they have a nice feature, where the second 128 bit number   
   is encoded as a four digit hex number. For example, if GDISK uses   
   0x0700 that is the old NTFS in a sense (0x07). But that is actually   
   a "Basic Data Partition" or ebd0a0a2-b9e5-4433-87c0-68b6b72699c7.   
   Linux uses that shorthand, mainly to not scare the shit out of the user :-)   
      
      https://en.wikipedia.org/wiki/Microsoft_basic_data_partition   
      
         "A basic data partition can be formatted with any file system,   
          although most commonly BDPs are formatted with the NTFS, exFAT,   
          or FAT32 file systems."   
      
   OK, so consider for a moment, that the ESP has a custom declaration.   
   This means there are custom properties, such as a "hands off, pal"   
   property. You cannot format it.   
      
   But there is a cheat :-) I know you'll like this. You can "dd"   
   over top of it.   
      
       sudo dd if=bunk.img  of=/dev/sda1   
      
   and now it's ruined. Easy, peasy. Similarly, you can make   
   a copy of the /dev/sda1, loopback mount it, format it FAT32,   
   unmount, dd over top of /dev/sda1. But there is still something   
   weird about that FAT32, that I haven't been able to put my finger on.   
      
   It's a brave new world. Lots of fun awaits :-) It took   
   me a while to find a weakness to exploit. I didn't know that   
   the first day I made a GPT. it might have been a year later.   
      
   Even figuring out the size of the partition table, was a menace.   
   Originally, I thought the partition table was 128MB.   
   It just might be 16KB (128*128) or so. A *lot* smaller than my pathetic   
   first info gleaned from some thread I was reading. You can take   
   your hex editor, scroll over the last cylinder of your disk   
   drive, and see the secondary partition table. If only   
   a few entries are occupied, the table looks very short indeed.   
   You could easily miss it.   
      
      [Picture]   
      
       https://i.postimg.cc/PqbrKYDr/gpt-secondary-table.gif   
      
   DISKPART> list partition   
      
     Partition ###  Type              Size     Offset   
     -------------  ----------------  -------  -------   
     Partition 1    System             100 MB  1024 KB  \   
     Partition 2    Reserved            16 MB   101 MB   \   
     Partition 3    Primary            118 GB   117 MB    \___ These are in the   
   above picture   
     Partition 4    Recovery           649 MB   118 GB    /   
     Partition 5    Primary            128 GB   119 GB   /   
     Partition 6    Recovery          1025 MB   248 GB   
     Partition 7    Primary            682 GB   249 GB   
      
   DISKPART> select partition 3   
      
   Partition 3 is now the selected partition.   
      
   DISKPART> detail partition   
      
   Partition 3   
   Type    : ebd0a0a2-b9e5-4433-87c0-68b6b72699c7   
   Hidden  : No   
   Required: No   
   Attrib  : 0000000000000000   
   Offset in Bytes: 122683392   
      
     Volume ###  Ltr  Label        Fs     Type        Size     Status     Info   
     ----------  ---  -----------  -----  ----------  -------  ---------  --------   
   * Volume 0     C   W11HOME      NTFS   Partition    118 GB  Healthy    Boot   
      
   DISKPART>   
      
      Paul   
      
   --- SoupGate-DOS v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)