When you ' by mistake said "Main" instead of "ISS"', you scrambled the configuration.
Do you still have the old ISS?
I would reinstall it to reset the eerom on the electronics module (emod).
When you install it, tell the printer you replaced the emod.
This will write the original config from the original ISS to the emod.
Afterwards, install the replacement ISS.
Select replace ISS when instructed on screen.
Should write the config to the EEROM and boot up normally.
If that fails, you need a new emod. I have them available at my website here:
Replacing the emod youtube channel instructions here: