I'm making a project with atmega328p-AU with a package TQFP and i programmer it through arduino ISP. I burned the bootloader of atmega328p 16MHz(because i used xtal 16Mhz on PCB) and i already programming it but the idea is working without the xtal. So, i removed the xtal and burn bootloader of atmega328p 8Mhz internal clock and the system worked fine. i made some tests with and without to optimize my project but one time i burn the bootloader atmega328p 8Mhz internal clock and appears this error:
avrdude: Yikes! Invalid device signature.
** Double check connections and try again, or use -F to override**
** this check.**
Erro ao gravar o bootloader.
After that, i can't burn any bootloader or upload any sketch.
Someone can help me?