I don't think there's really a "fix" for L2 and R2, it's just something you kind of have to work with. Whenever you configure the triggers, it'll probably do a double entry. So it will do something like 3- in L2 and then it will fill in R2 with 3+ as well. You can either go into your joypad configuration located in /opt/retropie/configs/all/retroarch-joypads/ and straighten things out manually. Or you can wait until you're at the bottom of the configuration, and you can scroll back up with the DPAD and redo the entries that aren't correct by pressing A and trying again. It's mostly just a mild annoyance after you've done it a few times, but it's something that when it happens the first time, it can be frustrating to figure out.

Ok thank you

@kruuth
When in the config menu, try

Setup / Configuration Edit RetroPie/Retroarch configurations Advanced Configuration Manually edit Retroarch configurations /all/retroarch.cfg

Hey that's sweet.
Thanks very much.

Yes, as it doesn't check if a keyboard is plugged in or not

https://retropie.org.uk/forum/topic/297/failed-failed-to-start-usbmount-dev-sda-service/2

@bamsi found a work around for same problem with my ps3 controller. I just manually configured retroarch settings in the retroarch menu. Watch video at link https://retropie.org.uk/forum/topic/100/made-some-progress-on-2-generic-shanwan-ps3-controllers-via-bluetooth-on-pi-3-retropie-3-6

I got it working with another bin + cue :)

Thanks everyone, I will experiment tonight with it!

try this..
config.txt settings

hdmi_group=1
hdmi_mode=6 or hdmi_mode=21

Even on PC, the 3DO emulators are very slow and buggy. In the end, for the games I have wanted to play, have found nearly all were released either for Dos or PSX. Games like Need For Speed, Return Fire, Fifa, etc.