I've got a backuptape in cpio format that was accidentally overwritten with a very small batch file. As I assume that the cpio header has been overwritten, I cannot extract files from the backup in the conventional manner:

( cpio -itv </dev/rct0
cpio: this is not a cpio file, bad header)

I've tried dd if=/dev/rct0 of=output which has produced a single large file The cpio actually records the contents of three directories. As these are large I'm hoping that I can recover data from the second and third directories.

Is there a specific dd expression (or any other expression) that I can use to strip out the contents ?

All suggestions appreciated. Thanks.

Martin