Unfortunately, the disk manager cart is required. I did see one on ebay
though.
 In a message dated 9/9/2008 2:49:58 A.M. Eastern
Daylight Time,   
snhirsch at 
gmail.com writes:
 I have just added a TI expansion unit to my
collection.  It came with all
the proper internal modules, but  there's a possibility that the Disk
Management plug-in cartridge  (firmware) is missing.  If the person I
bought it from is unable to  find it, is there any workaround to not
having this? 
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