How do you boot Unix 6 on an Ersatz-11 emulator?

Here is the e11.ini I have:

set cpu 40
mount dm0: ..\rk6.dsk
assign tt1: f2
assign tt2: f3

boot dm0:

The emulator currently displays the copyright, followed by a new line and an "@" symbol. At this point if you type "rkunix" or "unix" it has an exception...