Additional information not contained in the installation manual: 

MBR7ASPI.SYS: A new configuration line parameter has been added.
If you are trying to read a multisession Photo CD with more than approx.
4 recorded sessions and you receive a 'Not Ready' error message, 
the default timeout value may be too short. (The MBR-7 requires
time to find and read the TOC (table of contents) for each session
on a multisession CD.) In this case, add '/T' to the configuration
line. This will configure the driver for extended timeout.
For example:

DEVICE=MBR7ASPI.SYS /N:7 /D:MBRCD01 /T


There are two new files that have been added:
CDLOCK.COM
CDUNLOCK.COM

These files will be copied to the same directory used for the MBR-7
install. By typing CDLOCK at the DOS command prompt, the Disc Eject/Load
buttons on the MBR-7 front panel are disabled for all loaded discs. All
Eject/Load buttons can be re-enabled by using the CDUNLOCK command.


If you are updating a previous installation of the MBR-7 software, please turn off
the power to the MBR-7 and reboot your computer before running the installation
program.