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Baking up an MBR
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Baking up an MBR

guide

The MBR is stored in the the first 512 bytes of the disk. It consist of 3 parts:

|-----------------------446 bytes bootloader--------------------|------64 bytes partition table-------|-id-|

  1. The first 446 bytes contain the boot loader.

  2. The next 64 bytes contain the partition table (4 entries of 16 bytes each, one entry for each primary partition).

  3. The last 2 bytes contain an identifier

       # backup MBR
   dd if=/dev/sda of=/img/sda-mbr.img bs=512 count=1
   #restore
   dd if=/img/sda-mbr.img of=/dev/sda bs=512 count=1

   # backup partition table
   dd if=/dev/sda of=/img/sda-part.img seek=446 skip=446 bs=64 count=1
   dd if=/img/sda-part.img of=/dev/sda/ seek=446 skip=446 bs=64 count=1
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