I flashed my BIOS to that Multifirmware and its great... theirs a guide on how to do it somewhere... search for Flashing GP32 to Multifirmware or something
You do file->install in pc-link then select wind-ups in the free launcher. to get windups to start on boot up, use the flashing guide here faq.gp32emu.com and select 'Firmware Flashing'