You may write $IGR5 in your CHEATS.TXT file to have an OPL-like IGR (Select+Start+L1+L2+R1+R2 and no popup screen).
As for the black screen, I'm afraid that your BOOT.ELF is "incompatible" with POPStarter. The workaround is to disable the ELF loader (so it doesn't exit to BOOT.ELF), or maybe...