Take the generous salary offer. A startup takes years to build and from the looks of it you're jumping into an already failing mess for not much gain. 10% afte

Take the generous salary offer. A startup takes years to build and from the looks of it you're jumping into an already failing mess for not much gain. 10% after another round or two of funding will turn into not much for all the effort you will put in. If you're not getting a salary "at first" on top of this then you should run even faster in the other direction. Never work for free unless it's something you have complete control over and is something you're very passionate about. This has all the red flags of a bad situation and one you will more than likely get screwed over on down the road. If you want to found a startup I would suggest taking the lead dev job while you find something you are really passionate about to build.