Create a byte-perfect backup of the first 512 bytes so you can restore a damaged boot sector quickly. 16.11.2025 | reading time: 2 min A quick, reliable MBR backup can save a server after a failed bootloader update; this page shows how to create and restore a byte-accurate image with `dd` and simple checks. Rescue scenario Imagine a machine that fails to boot after a bootloader change: boot a live USB, open a terminal and run the commands below to save the first 512 bytes of `/dev/sda`, verify them, and restore if needed: ```dd if=/dev/sda of=/root/mbr.img bs=512 count=1 status=progress # sample output: "1+0 records in\n1+0 records out\n512 bytes copied" hexdump -C /root/mbr.img | head -n 5 # restore: dd if=/root/mbr.img of=/dev/sda bs=512 count=1 conv=fsync,status=progress # sample output: "1+0 records in\n1+0 records out\n512 bytes copied"``` Quick options to know Use `bs` to set block size and `count` to limit bytes; `bs=512 count=1` copies the complete MBR, `bs=446 count=1` copies only boot code, and `bs=1 skip=446 count=64` extracts the partition table; add `status=progress` to watch progress and `conv=fsync` to flush writes; beware that `dd` is powerful and a wrong `of=` will overwrite data, and remember GPT/UEFI systems use different boot structures so MBR backups are mainly relevant for legacy BIOS or the protective MBR region. Related utilities For partition-table and boot recovery use `sfdisk` to save and restore partition tables, `gdisk`/`parted` to work with GPT and MBR metadata, and `testdisk` to recover partitions; `hexdump` or `xxd` let you inspect the saved image, and `ddrescue` helps when reading failing disks. Next steps Practice on non-production disks, combine MBR images with filesystem backups, and script safe procedures; deepen your Linux skills and consider formal certification like CompTIA Linux+ or LPIC-1, and for focused exam preparation try the intensive courses at bitsandbytes.academy. Join Bits & Bytes Academy First class LINUX exam preparation. backup boot-process utilities storage troubleshooting
