efuse on arduino

[jamos.tan@gmail.com]

Thanks Sean, nice to meet you I have been following your work for a while now. Compliments!
I am using this instruction https://learn.adafruit.com/program-an-av...s?view=all
I have connected succesfully and verified with sudo avrdude -p atmega328p -C ~/avrdude_gpio.conf -c pi_1 -v

Now, I just need to know what to do now. I am unsure what correct fuse settings are and how to change it with AVR dude.
I've tried the instructions from https://forum.arduino.cc/index.php?topic=71580.0 and I was able to change the fuses succesfully.
However, after that I cannot flash it anymore with Arduino IDE sketch.

I have tried various fuse settings sugested in the previous mentioned link, but unsuccesfully.
USB is recognized succesfully still when I connect to the laptop, and a separate raspberry pi communicates through the GPIO is also OK.
It just doesn't flash anymore with the error:

avrdude: stk500_getsync() attempt 10 of 10: not in sync: resp=0xb1

I am not sure what to do now, do I:

- Upload a new bootloader?
- Which settings do I need for my Arduino Nano (for the fuses)

Hope you can help again.