Arduino NG or older bootloader not working on Atmega8A-PU

As in title, I used an arduino uno as ISP and burned atmega8a (+16MHz external crystal) Arduino NG or older (Atmega8 selected) bootloader but it dosen't work. But chip seems to be ok as if I program directly without bootloader the program works (Arduino as ISP programmer). Need help.

Please explain exactly what you mean by "it dosen't work"

Try a better set up for the Atmega8 parts. Add this to your IDE: https://github.com/MCUdude/MiniCore

You realize that if you upload a sketch via ISP, that erases the bootloader, right? You have to rebootload it before you can upload something over serial.

pert: Please explain exactly what you mean by "it dosen't work"

I mean after loader bootloader default blink program behaves like crazy. Led blinks twice and goes off for some time, and it repeats. But Upload using programmer (erasing bootloader, keeping just program) works clearly. But need the bootloader for UART programming.

Does it do that with the Minicore also?