SNES controller issue

I am running Lakka on a RPi3b with 2 SNES controllers attached through a USB adapter. It autoconfigured the Mayflash N64 adapter and after changing the Device Type to “RetroPad w/ Analog” and binding the buttons, both controllers work in the games, except that the first controller pauses the game and brings up the Lakka menu when I press the B button. If I bind the B function to another button I can play some games as long as they don’t use the other button. How can I either change the adapter to one that will work with SNES controllers or remap the Lakka menu to another button or button combination?