I think you are answering your own question. What's the likely hood of getting the upside on this? Let's say the funding does come through? Is that going to so

I think you are answering your own question. What's the likely hood of getting the upside on this? Let's say the funding does come through? Is that going to solve the problem? You can only answer this. Based on what you are saying, it's clear to me that you have a strong sense that this company may not survive. You need to ask yourself why you are still with the startup because based on what you are saying, there is a very high risk that the startup will shut-down in the next weeks, months. Based on all the information you have given, it looks like you are on a sinking ship. The problem is that you cannot afford to be on this ship. If you had the resources to stick around then it could be different. Being able to take on more debt does not mean you can do this. Don't set yourself back 3-4 years because you feel you owe the startup anything. At this point, they are not keeping up their end of the deal. If this was your startup and you were the founder, its a different dynamic. Why are you taking the same risk as the founders when your upside is so much less?