Chicken-and-egg problem -- you cannot mount the userstore to copy over kterm or a custom package.
...
Now, if you had kterm installed initially, you would not be in this situation. Because you would have a shell prompt running on your Kindle, you could do anything you needed without involving another device.
Or skipstone could be used to download things.
But as it is, you might need to use the serial port to get access to the internal storage. The serial port is separate from the USB port, it should still work.
