Using TIMER0_COMPB_vect
Your code doesn't do what you think it does. The timer always runs at 244Hz, and OCR0B only matches twice per period, causing it to have the same frequency but a different phase. What you need to do is set OC0B on compare match and clear it in the overflow ISR. OCR0A you can simply set to toggle on match.

TCCR0A = _BV(COM0A0) | _BV(COM0B1) | _BV(COM0B0) | _BV(WGM01);
TIMSK0 |= _BV(OCIE0A);

 ...

ISR(TIMER0_COMPA_vect)
{
  PORTB &amp;= ~_BV(PD5);
}


Also, OC0A is D6, not D4.