What is best sector by sector tool to copy bootable SDcard with Ubuntu and extras onto USB pendrive.

What is best sector by sector tool to copy bootable SDcard with Ubuntu and extras onto USB pendrive.

If by “sector-by-sector” you mean an exact block-level clone (so that boot sectors, partition table, unused space, and everything get carried), there are several good tools — which one is “best” depends a bit on your use case (speed, error tolerance, ability to shrink, etc.). Here are the top contenders and recommendations for copying a bootable Ubuntu + extras SD card over to a USB pen drive.

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Key considerations / caveats

Before diving into tools, here are a few things to check/think about:

• The destination USB must be at least as large (in total sectors) as the source SD card (or you’ll need a tool that can shrink or skip unused sectors).
• Any mounted partitions during the copy are a risk — you’ll want the source unmounted (or copied from a live / rescue environment).
• Some tools optimally skip unused sectors (i.e. do a “sparse” or “intelligent” clone) to reduce time and size.
• If there are bad sectors on the SD, you want a tool that handles read errors gracefully.
• After copying, you may need to adjust UUIDs, fstab, or bootloader entries if things reference the old disk name or UUID.

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Good tools for sector/block-level cloning

Here are several good tools for doing a full (or close to full) clone. Each has pros and cons.

Tool	Pros	Cons / caveats	Suggested use-case
dd (disk duplication)	Built-in, ubiquitous, simple to use	Copies all sectors including unused ones; doesn’t handle read errors gracefully; can be slow for large disks	When source and target are identical size and reliable media
ddrescue / GNU ddrescue	More advanced; can recover from read errors; keeps a map-file	More complex syntax; might require multiple passes	Best when source media is old or might have read errors (Wikipedia)
dd_rescue	Like dd but better error handling than plain dd	Less common; fewer features than ddrescue	Alternative to ddrescue
partclone / partimage etc.	Clone only used sectors of partitions	Needs working filesystem support for each partition type; may not clone boot sectors or special partitions directly	When you want faster clone and are comfortable manipulating partition boundaries
Clonezilla	Full-featured, supports many file systems, supports cloning disk to disk or to image, handles partition resize	Needs booting into Clonezilla environment; GUI or curses interface	General purpose, safer and flexible cloning
Raspberry Pi’s SD Card Copier (if you’re cloning from a Pi environment)	GUI, tailored for copying running system	Less control, may not do full sector-level cloning	Good for Raspberry Pi use-cases (Raspberry Pi Stack Exchange)

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What I’d pick for your case (Ubuntu SD → USB pen drive)

Given your description (“Ubuntu + extras” on an SD, copying to a USB), here’s what I would pick and how to use it:

Option A: ddrescue (preferred for robustness)

1. Boot from a live USB or another system so your SD is not mounted.
2. Use lsblk or fdisk -l to identify the source device (e.g. /dev/sdb) and the target (e.g. /dev/sdc).
3. Run something like:

4.  sudo ddrescue -f -n /dev/sdb /dev/sdc mapfile

Here,

4. -f forces overwrite of the destination,
5. -n means “no retry” (fast first pass),
6. mapfile records which sectors succeeded, so you can do later stages (with retries) if needed.
7. Optionally run a second pass to recover leftover sectors:

6.  sudo ddrescue -d -r3 /dev/sdb /dev/sdc mapfile

(That will attempt retries up to 3 times on bad sectors.)

7. After copying, check partitions, run fsck, update fstab or bootloader if required.

This method gives you a robust clone, even if there were some read errors on the SD.

Option B: dd (for simple, clean media)

If your SD is in good condition and the USB drive is equal or larger:

sudo dd if=/dev/sdb of=/dev/sdc bs=4M status=progress conv=notrunc,fsync

• bs=4M helps with speed.
• status=progress shows copying progress.
• conv=fsync ensures writes are flushed.

Make sure both source and destination are unmounted before running. This is the “classic” way. Many guides (e.g. for SD card cloning) use dd. (Ask Ubuntu)

Option C: Clonezilla (if you want GUI / interactive features)

• Boot into Clonezilla live.
• Choose “device-to-device” clone (i.e., SD card → USB).
• You can opt to skip unused sectors, choose to check / resize partitions, etc.
• Proceed and let it clone.

This approach gives you more safety checks (you see interactive menus) and flexibility.

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Summary

• Best “all-round” tool (in my view) = ddrescue (because of error handling and robustness).
• For clean media and maximal simplicity, dd works fine.
• If you prefer an interactive tool with safety, go with Clonezilla.

How about windows tool?

Good question — if you’re doing the cloning on Windows, there are a few excellent tools that can do true sector-by-sector copies from an SD card to a USB drive.

Here are the most reliable Windows options for your use case (bootable Ubuntu SD → USB pen drive):

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🥇 Win32 Disk Imager — Simple, reliable classic

✅ Pros

• Free & lightweight.
• Does true sector-by-sector reads and writes.
• Very widely used for Raspberry Pi / bootable Linux cards.
• Works with any removable storage — SD → USB included.

⚠️ Cons

• No error recovery.
• Destination drive must be at least the same size as the source.
• No partition resizing.

🧰 How to use

1. Insert the SD card and the USB drive.
2. Run Win32 Disk Imager as Administrator.
3. Read from SD to an image file (.img):
   • Select the SD card as the source device.
   • Choose a filename and click “Read”.
4. Write the image file to the USB drive:
   • Select the USB drive as the target.
   • Select the .img file.
   • Click “Write”.

✅ You now have a bootable, exact clone of the SD card on the USB pen drive.

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🥈 USB Image Tool — Very clean interface, simple workflow

✅ Pros

• Freeware and portable (no installation needed).
• Sector-by-sector backup and restore.
• Friendly GUI with device list.
• Handles most USB sticks and SD cards via a reader.

⚠️ Cons

• Like Win32 Disk Imager, no resizing.
• Needs the target USB to be at least the same size.

🧰 How to use

1. Open USB Image Tool.
2. Select the SD card device.
3. Click Backup → save .img file.
4. Select the USB pen drive.
5. Click Restore → choose the .img file.

📝 This tool is very popular among Raspberry Pi users for cloning systems to and from USB.

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🥉 HDD Raw Copy Tool — Good for mixed or flaky media

✅ Pros

• Freeware.
• Sector-by-sector clone, including boot sectors and partition tables.
• Can clone directly from device to device (no intermediate image file needed).
• Handles larger drives gracefully.
• Works well even if SD card is slightly damaged.

⚠️ Cons

• Less polished UI.
• No partition resizing or editing.

🧰 How to use

1. Start HDD Raw Copy Tool.
2. Choose the SD card as source.
3. Choose the USB drive as target.
4. Click “Continue” → then “Start” to begin cloning.

🚀 It copies everything bit-for-bit, so the resulting USB should boot exactly like the SD.

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Summary — Best Windows sector copy tools

Tool	Type	Image intermediate	Handles errors	Bootable clone	Easiest
Win32 Disk Imager	Classic	Yes	❌	✅	⭐⭐⭐
USB Image Tool	Simple GUI	Yes	❌	✅	⭐⭐⭐⭐
HDD Raw Copy Tool	Direct device clone	Optional	✅	✅	⭐⭐⭐

👉 My recommendation:

• If the SD card is healthy → USB Image Tool (easiest).
• If you suspect read issues or want direct SD→USB without making an image → HDD Raw Copy Tool.
• If you prefer something tried and true for Raspberry Pi systems → Win32 Disk Imager.

How do you use dd command in Linux to copy SD card to USB3 drive?

Good question — using the dd command under Linux is a very clean way to do a sector-by-sector clone of your SD card straight to a USB 3.0 flash drive.

Here’s a clear, step-by-step guide to do it safely and efficiently 👇

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🧰 What you need

• Your SD card (the source).
• Your USB 3.0 pen drive (the destination).
• Root privileges (sudo).
• The target USB must be equal or larger in capacity than the SD card.
• Make sure both are unmounted before starting.

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🪜 STEP 1 — Identify the devices

Plug in both drives and run:

lsblk

You’ll see something like:

NAME   MAJ:MIN RM  SIZE RO TYPE MOUNTPOINTS

sda      8:0    0 500G  0 disk

├─sda1   8:1    0 200G  0 part /

└─sda2   8:2    0 300G  0 part /home

sdb      8:16   1  32G  0 disk

└─sdb1   8:17   1  32G  0 part

sdc      8:32   1  32G  0 disk

└─sdc1   8:33   1  32G  0 part

• Suppose /dev/sdb is your SD card.
• And /dev/sdc is your USB 3.0 stick.

👉 Important: use the whole device (/dev/sdX), not the partition (/dev/sdX1).

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🪛 STEP 2 — Unmount any partitions

If either device has auto-mounted, unmount it:

sudo umount /dev/sdb1

sudo umount /dev/sdc1

(Do this for all partitions if needed.)

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📤 STEP 3 — Run dd to clone

Here’s the recommended command:

sudo dd if=/dev/sdb of=/dev/sdc bs=4M status=progress conv=fsync

Explanation:

• if=/dev/sdb → input file = SD card
• of=/dev/sdc → output file = USB stick
• bs=4M → copy in 4 MB blocks (much faster than default)
• status=progress → shows live progress during the copy
• conv=fsync → ensures data is fully written before finishing

👉 If the USB stick is slightly larger than the SD card, the copy will still work fine.
👉 If it’s smaller, dd will fail when it runs out of space.

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⏳ STEP 4 — Wait patiently

• dd doesn’t show a time estimate, just the amount copied and speed.
• Don’t interrupt it unless absolutely necessary.
• When it finishes, you’ll see something like:

8192+0 records in

8192+0 records out

34359738368 bytes (34 GB) copied, 300 s, 114 MB/s

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🔄 STEP 5 — Sync & eject

Force all buffers to be flushed:

sync

Then safely remove the drives.

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🧪 STEP 6 — (Optional) Verify clone

You can compare the two devices byte for byte:

sudo cmp /dev/sdb /dev/sdc

If it returns nothing, they are identical ✅

Or generate a checksum:

sudo sha256sum /dev/sdb

sudo sha256sum /dev/sdc

The two hashes should match exactly.

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📝 Tips & optional improvements

• Speed up on fast devices:
  You can increase bs (e.g. bs=16M), but 4 MB is a safe default.
• Preserve terminal usability:
  Add & at the end or use pv if installed:

·         sudo dd if=/dev/sdb bs=4M | pv | sudo dd of=/dev/sdc bs=4M conv=fsync

• Error handling:
  For potentially damaged SD cards, it’s better to use
  GNU ddrescue instead of dd — it retries bad sectors.

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✅ Result: your USB 3.0 stick is now a bit-for-bit clone of the SD card — fully bootable if the SD was.