What is required to enable Save to USB?

A.
Host USB plug and play must be enabled in the EWS.

B.
The printing port TCP/IP 9100 must be disabled.

C.
The Administrator password must be set.

D.
The USB device must use FAT16 file system.

Explanation:
Reference:ftp://ftp.hp.com/pub/networking/software/pfirmware/readme_cljCM4540fw_2300333_37
8001.pdf(page 15, 19th bullet)