I have tracked down some issues with the file mac-files.c. The one big issue is with a variable called str. It isn't set properly. When I type this command "dir cd:9,\Utilities", str should be set to "9,\Utilities". argstr should then be set to "\Utilities". This does not happen. Instead str is set to "9".
I traced the issue with a function called my_args_copy(). That led me to a forth word called my-args. I'm not sure what this word does, or where it is defined.
Reading some of the comments in various files, someone thinks that if no partition is specified, it means the whole disk is selected. My plan is to change this so that is no partition is selected, it means to select the first Apple_HFS or Apple_HSFX partition. If someone wants to use an entire disk, they have to explicitly specify it by using zero as the partition number. This fix should make automatically selecting a partition work.
Hope this makes sense.