The v6.0x Firmwares will have to be net booted on some 5861s as they will not fit into the smaller memory of a 1 Meg 5861s since they were made for 2 Meg 5861s.
EDITED: It looks like you have the 2 MB Flash Rapid Secure versions aka 060-5861-0xx.
EDITED: You should read as many articles here that are available and the last article is about Netbooting only if you have any 120-5861-0xx units with the smaller Flash memory.
