The only other " button " I'm aware of is the microswitch for the light.
As to the problem. Firstly I'm about to teach you to suck eggs. You are aware that the button boot release only works when the ignition is " OFF " ?
I understand you mentioning the "off" but yes it is off when trying, it has been working fine up until the weekend, so now now it goes onto the list of problems.
1. Passenger electric window not working in hot conditions.
2. Vehicle spasmodically not starting until steering wheel is moved up and down.
3. Glove box boot release not working.
4. Top spasmodically not going up until motor tapped with hammer
I was warned time and time again that I would have a lot of electrical problems with a Spider, should have listened...