yes, you cannot do this in the inventor, as the file you need to edit is the system-global params.cfg, not your own module's params.cfg. The system-global params.cfg is parsed once when jevois boots up. It is not available in the Inventor because any changes in this file will likely break communication between the Inventor and JeVois, so the system-global params.cfg is for advanced users only. In contrast, a module's params.cfg is parsed each time that module is loaded.
To access it: insert your microSD into your PC using an adapter (card reader). You need a Mac or Linux machine, Windows only detects the first partition of SD cards, but the file is on the third partition (called JEVOIS). Alternatively, in the Inventor go to the System tab and enable exporting the microSD inside JeVois as a virtual flash drive. The JEVOIS partition will then appear on your computer as if you had attached a flash drive. Then edit the file:
using a plain text editor.