Is it possible to write MBR of a pen drive by any hex editor?

2012-08-30

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Question

After creating the boot loader, if I copy the bytes of the boot loader and paste it on the 1st 512 bytes of the pen drive using a hex editor, will it work? (Actually I want to learn creating an operating system from scratch.)

Answer

I'm not entirely sure I understand your question, but to answer the title: yes. You can write to any part of the drive with an appropriately-designed hex editor with appropriate permissions (usually "sudo" access is required on Linux).

For instance, writing to the boot sector of a flash drive is necessary for automating booting of the CHDK system.

Not all hex editors are designed to access drives, some can only work with files. For instance, the NCurses Hexeditor normally works only with files, but can be made to access disks as files in Linux/Unix environment by employing the -d flag.

The Linux dd command also enables low-level writing to drives. This may be useful in your case as it can be used to perform byte-by-byte copies of drive contents, including MBR sections.