Update Arduboy2 library to 5.2.1 bootloader support for alternate flash chipselect SDA reverted Sprites.cpp added checkBatteryState checkBatteryStateLED functions to Arduboy2 library update cathy3K bootloader with menu scrolling and progressbar
Add bootloader support for Flash cart using SDA (pin 2/ D1) as chip select.
Added all source files except the libraries (too many files to add in a single go)