Possable inaccuracy in DS3100 installation manual

[Kurt L. Reisler]

In the installation documentation for the DECStation 3100 (YES!  I read
it!) it IMPLIES that you can place any of the peripherals (disk, tape,
optical disk, etc) on any of the 6 port addresses that are available.
Doing a "test -c" at the prom prompt will list what devices are on what
ports.  You then use this information during the installation process.

However, if you have the TZK50 (tape cartridge) on any port other than
port 5, when you attempt to boot, you are informed that the device on
that port is busy.  If you install the tape on port 5, it will boot
properly.

Is this an error on my part, was there a part of the documentation that
I missed, or is the boot prom looking for the tape drive to ONLY be on
port 5?