Hi @btrue!
For legacy reasons, ArduSub actually expects the Z axis to be 0 to +1000, which is likely the cause of your issue.
That should already be the default in Cockpit when a Sub vehicle is connected, so I’m curious how that ended up changed for your setup. We really aught to add a warning for that though - it shouldn’t be so easy to end up with values that don’t work properly. I’ve raised an Issue for it.
Yeah, booting can take a while unfortunately. We have looked into some potential improvements, but have prioritised other things so far.