Does the hard disk have just one partition? If so, boot from a live CD (or from a floppy loaded with something like Tom's Root Boot
), and do
dd if=/dev/hda of=/dev/sda bs=512
Note that this copies one device
to the flash drive, deleting anything on the flash drive, including any partitions, master boot record, bootloader, etc. A conventional format can be easily restored once you have offloaded the content to spinning media, or whatever you want to do with it.
If you only want to save the partition data, then instead, do
dd if=/dev/hda1 of=/dev/sda1 bs=512
(Use partition numbers as appropriate).