1) Regarding downgrading to 2.0.0, the issue was because you used ‘-p m328p’ in the command. It should be ‘-p m644’ because OpenSprinkler 2.0 uses ATmega644 microcontroller, not mega328.
2) Regarding microSD card problem, how did you format the SD card? I’ve had issues when formatting the card in Linux. It should be formatted to FAT16. Somehow when I formatted it in Linux it wasn’t recognizable, but it was fine when formatted in Windows. I will investigate the issue later.