TryHackMe Walkthrough: MBR and GPT Analysis (Beginner to Intermediate Guide)

Let's break down the structure of MBR (Master Boot Record) and its components, focusing on how it functions to load an operating system during a computer startup.

Structure of MBR

The MBR occupies exactly 512 bytes at the very beginning of a disk (starting from sector 0). It can be divided into two main sections:

1. Bootstrap Code (Bytes 0–445)

   • This section contains code that is executed by BIOS when the computer starts up.
   • Its primary job is to read and execute the second-stage bootloader, which resides in one of the four partitions marked as bootable.

2. Partition Table (Bytes 446–509)

   • The partition table consists of 16-byte entries for each of the four possible partitions.
   • Each entry contains crucial information about a single partition:
     • Boot indicator: A flag indicating if this partition is bootable.
     • Starting CHS address (Cylinder, Head, Sector): Where the partition starts on the disk.
     • System ID: An identifier for the file system type (e.g., 07h for NTFS).
     • Ending CHS address: Where

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