Code:
 bt changes=/dev/device
All changes you made in BT are kept in memory until you reboot. But with this boot parameter, you tell BT to use a different device than memory for storing changes. You can, for example, format your disk partition /dev/hda1 with some Linux filesystem (eg. ext2) and then use changes=/dev/hda1 to store all changes to that disk. This way you won't loose your changes after reboot.
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