First, there is no need to futz about with your own board def, just install MiniCore - GitHub - MCUdude/MiniCore: Arduino hardware package for ATmega8, ATmega48, ATmega88, ATmega168, ATmega328 and ATmega328PB - has everything all set up for almost any conceivable clock speed and set of configuration options for the atmega x8/x8p/x8pb parts - it is by far the easiest way to work with bare-bones/custom atmega-based boards that don't match the clock configuration of an official board (he also maintains similar cores for the atmega x4 (MightyCore) and x1/x0 (MegaCore), and the megaavr x08 and x09 series (MegaCoreX), just like I do for the ATtiny parts).
But that's not related to the issue at hand - either you have a wiring mistake, or the chip was previously set to use an external crystal (in which case, you need to provide a crystal or clock source in order to program it not to expect one).
By the way - you do realize that no matter what, you need a 0.1uF ceramic cap between vcc and ground pin, and avcc and gnd, and these must be right next to the chip. Without these, the part may reset or hang seemingly at random; these "decoupling caps" are needed between power and ground on all digital ICs, 0.1uF unless datasheet says otherwise), and they always need to be as close to the part as possible.