raspberry pi – SDcard Image behaves differently than Original

When creating a disk image of an existing system, you should do it with a separate operating system, not while the system is running, as this could introduce errors.

For example, you boot an OS and use it to create a disk image of your SD card containing Raspberry OS.

You can save it to the hard drive or directly clone the SD card to a new one using dd.

With SD cards, you need to be careful because they wear out faster compared to USB sticks, SSDs, M.2, or HDDs, especially with many read/write operations, which can damage sectors over time.

Make sure the SD card is not used or to much used.

When using dd, I personally always use the block size value of 1M:

dd if=/dev/SDCARD1 of=/dev/SDCARD2 bs=1M status=progress

dd if=/dev/SDCARD1 of=/PATH/OS-IMAGE.img bs=1M status=progress

The bs=1M value in dd sets the block size to 1 megabyte, meaning data is read and written in chunks of 1 MB at a time using bs=4M or other in dd increases the block size to 4 megabytes, which can speed up the process by reading and writing larger chunks at once, but the optimal size depends on the system’s performance and storage device