Set the bootloader lock bits.


In this context, a 'set bit' will be written to a zero value. Note also that only BLBxx bits can be programmed by this command.

For example, to disallow the SPM instruction from writing to the Boot Loader memory section of flash, you would use this macro as such:
    boot_lock_bits_set (_BV (BLB11));

Like any lock bits, the Boot Loader Lock Bits, once set, cannot be cleared again except by a chip erase which will in turn also erase the boot loader itself.