I have a nonlinear two-point boundary value problem consisting of five first-order differential equations. There are three boundary conditions at t=0 and two at t=1. Each boundary condition set also has one unknown parameter, along with an additional constraint. I want to solve this problem using collocation, as it is expected to be stiff under some conditions. SciML gives a very clear example of using collocation to solve the Mathieu equation with one unknown parameter by setting “fit_parameters = true” in the BVP constructor. However, my problem differs from this example in two important ways: 1) The two unknown parameters are in the boundary conditions, not the differential equations. 2) Both the differential equations and the boundary conditions depend on a number of KNOWN parameters, currently in the vector p, and I don’t want the solver to attempt to fit those. The Mathieu example only has the one unknown parameter in p. Any help or advice would be appreciated. I’m very sorry, but I’m not able to share any actual code in a public forum.