Getting the error “./upgrade_tool: command not found” usually means you're using a MAC M-series machine. These machines have an ARM architecture, and this tool doesn't work with it. Right now, the tools Rockchip offers don't support MAC very well. That's why we don't usually suggest using a MAC for development.

The Maskrom mode kicks in when the system can't detect a storage medium or can't find the Miniloader in the storage medium. With the RKDevTool, all you can do is the burning operation. You can only load the Miniloader and get the current storage medium when you're in the FASTBOOT mode.