I've modified the OS 3.9 emergency disk to boot from a network drive. Actually it mounts an ISO image of the OS 3.9 CD stored on the network drive instead of the real CD. But it could as well be made to boot from a directory on the net drive.
It's similar to the CF card approach above with the difference that my solution works while hardlink's doesn't because the X-Surf cannot boot from its IDE port. You'd have to connect the CF card to the motherboard IDE port instead.
