Using dd to dump Android partitions via adb

Unfortunately there are some pitfalls, e.g. \n is converted to \n\r which is rather annoying in binary data.

Works as expected

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$ adb exec-out 'dd if=/dev/block/mmcblk0p1 2>/dev/null' > mmcblk0p1.bin

Also works as expected, but once resulted in a dump missing 2 bytes (could not be reproduced)

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$ adb shell 'dd if=/dev/block/mmcblk0p1 2>/dev/null' | sed 's/\r$//' > mmcblk0p1.img

This results in the said conversion (DON’T USE THIS)

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$ adb shell 'dd if=/dev/block/mmcblk0p1 2>/dev/null' > test.img

Broken images can be fixed with

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$ sed 's/\r$//' < test.img > test.bin

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$ cat test.img | sed 's/\r$//' > test.bin

This also doesn’t work as expected

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$ adb shell 'stty raw && dd if=/dev/block/mmcblk0p1 2>/dev/null' > mmcblk0p1.img

Restoring a partition is straightforward though

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$ adb push mmcblk0p1.bin /dev/block/mmcblk0p1