Confirms via code inspection that the firmware isn't uniformly driven
by MAIN_Fosc: Uart1_Init()'s Timer2 baud-rate reload and rf.c/timer.c's
tick-to-microsecond conversion assume an actual 24MHz clock as
hardcoded constants, not values computed from MAIN_Fosc. Flashing at a
different STC-ISP clock setting would silently break UART baud rate
and RF timing without an obvious compile error.
cbd480eea3