I am trying to set an atmega328p to use its internal oscillator, firstly I downloaded and extracted to the "hardware" file the zip as instructed in the tutorial, all went well. When I started using the IDE to compile and upload any sketches I now get a warning that reads....Warning: Board Breadboard Arduino: Avr: atmega 328bb doesn't define a 'build board' preference. Auto-Set to: AVR_ATMEGA328BB...…….I get this warning now every time I use the IDE regardless of sketch. I now went to burn the bootloader and again followed the tutorial (and may others on u-tube) and I always get the same error :-Arduino: 1.8.5 (Windows 10), Board: "ATmega328 on a breadboard (8 MHz internal clock)"
avrdude: Yikes! Invalid device signature. Double check connections and try again, or use -F to override this check.
Error while burning bootloader.
This report would have more information with "Show verbose output during compilation" option enabled in File -> Preferences.
I have tried re-wiring several times, check supply and gnd, I have "buzzed out" my cables tried swoping chips from host to target (both run blink ok) and many other things. I un-installed the IDE and deleted the hardware file and the Arduino directory and did a clean install. I found after completing this the warning still came up which I don't understand as it was a new install I then downloaded the correct zip to the hardware file I had newly created in the sketch folder tried to burn bootloader and got the same error as above. I also don't no what "or use -F to override this check" means? Please can you help me ?