I need to change the IP address of my fr20 robot with FRC100-AC-5000-A control box, firmware v3.8.0.1, but it is unclear how to restore the default IP if something goes wrong

Using the WebUI, I have changed the ip address for eth0 from 192.168.57.2 to 192.168.56.2

I have found differing sources saying that in order to restore the default IP address on the robot, I need to hold the reset IP button for 30 seconds, Maybe wait for a green light to blink a couple times, maybe power cycle after holding the button down, or maybe hold the reset ip button while powering on the robot.

I have tried all of these permutations, and the ip address above never gets restored to 192.168.57.2

eth1 is the configuration used for accessing the WebUI, so i am hesitant to make any changes there for fear of getting locked out since the previous reset behavior didnt work.

The target IP for my system is 10.0.0.101. I have tried setting eth0 to the 10.x.x.x network, but apparently the default gateway and dns server between eth0 and eth1 are linked. Changing one automatically updates the other. If I try to set the ip address of eth 0 to 10.0.0.101, and leave the default gateway as 192.168.58.1, then an error pops up saying "subnet mask or default gateway or dns format error". 

1. given my hardware listed above, how can I reliably reset the ip address of my robot if something were to go wrong? If there's a reliable way to do this, then the other questions are probably irrelevant.

2. If I change eth1 from 192.168.58.2 to another subnet (e.g., 10.0.1.101), will the WebUI automatically bind to that new address (i.e., be reachable at http://10.0.1.101), or is it fixed to the 58.x interface?
3. Is there any recovery mechanism using the usb port on the control box?