Just in case for someone still have a trouble.
Following this link GitHub - MCUdude/MiniCore: Arduino hardware package for ATmega8, ATmega48, ATmega88, ATmega168, ATmega328 and ATmega328PB
and it work with ATmega8 & ATmega48.
In order to my testing, it also works with:
- ATmega8A, and
- ATmega8L, and
- ATmega48V