I have been working on a custom CCA that utilizes the ATMEGA328P as the microcontroller and up to this point have been purchasing it with the bootloader already installed from Adafruit which apparently uses their ADAboot version of the bootloader, https://www.adafruit.com/product/123. My problem is they are low on stock and thus I'm wondering what the impacts would be if I try to use other vendors' preprogrammed ATMEGA328Ps with either the Opti bootloader or the "Arduino 16MHz" bootloader. Some details of my design: Use an external resonator to run the chip at 2MHz, I also run the part at 3.3VDC. I program through a small header on my board using a FTDI cable. I spent a significant amount of time adjusting the code and boards.txt file to make my custom design work and at the end of the day I just want to be able to program the chip in the same manner I do today and I'm not sure that is affected by the different bootloader.