Well, I suppose that's a good thing so they can be fixed or amended to work properly. :)
Here's how to reproduce the issue (it makes no difference in the dosbox.conf which joystick type is selected or even if left alone as auto/default joystick): Map some keyboard keys to P1 controller buttons, including some being mapped to P1's d-pad in the control mapper (CTRL+F1); Map some keyboard keys to P2 controller buttons, including some being mapped to P2's d-pad (same as above); Boot the game with no pads connected or turned on / connected = game will not boot Boot the game with only 1 joypad...
Here's how to reproduce the issue (it makes no difference in the dosbox.conf which joystick type is selected or even if left alone as auto/default joystick): Map some keyboard keys to P1 controller buttons, including some being mapped to P1's d-pad in the control mapper (CTRL+F1); Map some keyboard keys to P2 controller buttons, including some being mapped to P2's d-pad (same as above); Boot the game with no pads connected or turned on / connected = game will not boot Boot the game with only 1 joypad...
This is a workaround but I believe you cannot map the D-Pad to P2 controller, but mapping the D-Pad to P1 is fine. Games boot then (regardless of how many controllers are connected).