Did you follow the instructions for downloading and compiling the latest software updates for github?
Assuming you have the latest software, these are the command that I used to change the gripper2 ID from the default of 1 to the required value of 12.
1. stop the niryo one service
sudo systemctl stop niryo_one_ros.service
2. change directory to the debug tools folder
3. scan the dxl bus for connected IDs (it should show IDs 2, 3, 6, and 1 on a version 2 hardware)
Note: two hyphens before scan
4. change the ID of the motor from 1 to 12
Note: two hyphens before set-register
./dxl_debug_tools -i1 –set-register 3 12 1
5. change directory back to root
6. restart the niryo one service
sudo systemctl start niryo_one_ros.service
Hopefully this help you. I know it took me some time to figure out the correct format for entering the commands.